Roblox Error Code 277 and 279 Explained: Lost Connection, ID 17, the UDP Port Range, and the Official Fix Order
Posted: Wed Oct 21, 2026 12:35 pm
Quick Summary
Roblox describes error 277 as a lost connection to the game server. The client and the server stopped talking, and the client gives up.[1] Roblox says it happens "when the client application servers fail to establish a network connection on PCs, Macs, or mobile devices".[1] In practice you are playing, then the screen freezes, then you are back in the lobby or on the website.
The important detail is that 277 is a drop, not a rejection. Your account is fine and your game progress is fine. The session ended early. That is why reinstalling Roblox, which fixes corrupted files, sits at the top of Roblox's own fix list for this code.[1]
What Error Code 279 / ID 17 Actually Means
Error 279 is the join-time version. Roblox's help article is titled "Error Code 279/ID 17: Failed to connect to the Game", and it applies to PCs, Macs and mobile devices where "the client application and servers are having trouble establishing a network connection".[2]
Players tend to see two things under this code. One is a plain 279 popup. The other is the older wording, "Could Not Connect" or "ID=17 Failure". Roblox lists both under its general connection symptoms.[3] If you can open an experience in Build or Edit mode but not in Play mode, that is a classic connection problem rather than a broken install.[3]
First Check Whether Roblox Is Down
Roblox runs a public status page at status.roblox.com. It reports each component separately, including Website, Mobile App, Xbox App, Games, Studio, Game Join and Marketplace, and it keeps a 30-day incident history.[4] When the Game Join component is degraded, you cannot join anything and the error looks like it came from your computer.
Recent history on that page is useful context. Roblox logged a degraded performance incident on October 5, 2026 affecting the User, Player and Creator components, which it identified at 16:04 PDT and resolved at 16:13 PDT, and a separate Studio publish disruption on September 28, 2026 that ran from 16:05 to 19:18 PDT.[4]
Third-party trackers see the same pattern. Downdetector's Roblox page reports the most common problems as server connection, game launch and game play.[6] DownForEveryoneOrJustMe records the same October 5, 2026 outage at about 47 minutes, and notes that launching the game is the single most reported Roblox problem across its data.[7]
So before you touch a firewall setting, open the status page. If everything reads Operational and you still cannot connect, the problem is almost certainly on your side of the router.[4]
The Port Range That Gets Blocked
Roblox does not use one fixed outgoing port. The client scans for a free port on your machine and assigns ports dynamically for each experience session.[9] Roblox publishes the range it expects to be available as UDP 49152 to 65535.[3][8]
That range matters more than most guides admit. Because the client picks a port at random inside it, blocking a single port number often does nothing, while blocking the whole range breaks every join attempt. If your router blocks UDP packets on any port in that span, Roblox will not connect.[9] Roblox recommends contacting your ISP if the ports need to be opened or activated on the router.[8]
Fix Order: Roblox's Own Steps
What To Do When You Reinstall
Roblox's reinstall guidance is more specific than most guides suggest. On Windows you usually do not need to uninstall first, because the reinstall overwrites deleted or broken files. If reinstalling does not work, uninstall, restart the computer, then reinstall. Roblox also asks you to delete your browser's temporary internet files and cookies, and to make sure every other program is closed during the install.[10]
On Mac, the flow is different. Quit Roblox completely, uninstall, then open Safari, log in and start playing. The installer prompt should appear. If it does not, go to Finder, open Today, and click Roblox.dmg to run the installer.[10]
Other Roblox Error Codes Worth Knowing
Roblox keeps a master index of error codes, and it is the fastest way to identify a code you have not seen before. The index covers 264, 266, 267, 268, 270, 277, 279 and ID 17, 280, 403, 524, 600, plus "Failed to Load Library".[5]
Two of those are easy to confuse with connection problems. Error code 280 says your version of Roblox may be out of date and asks you to update, which is a different fix from 277 or 279.[5] Error code 403 means access to the page was denied and you are not authorised to view it.[5] If your code is not in that index at all, Roblox asks you to contact its support team.[5]
FAQ
Why do I keep getting error code 277 in Roblox?
Because the client lost its network connection to the game server mid-session.[1] Roblox's own first-line fixes are reinstalling the application, clearing the local app data, and trying a different internet source.[1] If the error follows you onto a different network, the cause is on your machine rather than your connection.
How do I fix error code 279 on Roblox?
Start with the status page, then try a different internet source, then reinstall Roblox and clear the app data, then check the date and time.[2] If you play in a browser, switch to Edge, Firefox or Chrome and remove any ad-blockers, which Roblox says can stop an experience loading.[3]
Does Roblox error 277 mean my account is banned?
No. Error 277 is a network error, not a moderation action. Roblox defines it as a lost connection to the game server, and the fix list is entirely about network access, corrupted files and clock settings.[1] If the account itself were the problem you would see a different message.
What ports does Roblox use?
Roblox says the port range is UDP 49152 to 65535, and the ports the client uses depend on the operating system.[3][8] The client scans for a free port on your machine and assigns them dynamically per session, so blocking any UDP port in that range can break joins.[9]
How do I check if Roblox is down right now?
Open status.roblox.com, which reports each component separately and keeps a 30-day incident history.[4] Cross-check with Downdetector, which lists the most common Roblox problems as server connection, game launch and game play.[6]
My antivirus flagged Roblox. Is Roblox safe?
Roblox addresses this directly in its third-party applications article, telling users to flag the warning as a false positive and add Roblox to the antivirus exceptions list.[8] On Windows the Roblox files sit in [c]C:\Users\(Your Windows Username)\AppData\Local\Roblox[/c].[8] Only add the exclusion if you installed Roblox from the official site.
Sources
- Roblox error codes 277 and 279 mean your client could not keep or establish a network connection to the game servers.[1][2]
- Error 277 shows up after you are already in a game and get dropped. Error 279 stops you at the join screen, and is often labelled ID=17.[1][2]
- Most of these errors are local. Firewalls, antivirus software, ad-blockers and router port blocks are the usual suspects.[3][8][9]
- Before changing anything, check whether Roblox itself is down, because a platform outage looks exactly like a broken connection on your end.[4][6]
- The fixes below are the ones Roblox publishes, in the order it publishes them. Work down the list and stop when one of them lands.[1][3]
Roblox describes error 277 as a lost connection to the game server. The client and the server stopped talking, and the client gives up.[1] Roblox says it happens "when the client application servers fail to establish a network connection on PCs, Macs, or mobile devices".[1] In practice you are playing, then the screen freezes, then you are back in the lobby or on the website.
The important detail is that 277 is a drop, not a rejection. Your account is fine and your game progress is fine. The session ended early. That is why reinstalling Roblox, which fixes corrupted files, sits at the top of Roblox's own fix list for this code.[1]
What Error Code 279 / ID 17 Actually Means
Error 279 is the join-time version. Roblox's help article is titled "Error Code 279/ID 17: Failed to connect to the Game", and it applies to PCs, Macs and mobile devices where "the client application and servers are having trouble establishing a network connection".[2]
Players tend to see two things under this code. One is a plain 279 popup. The other is the older wording, "Could Not Connect" or "ID=17 Failure". Roblox lists both under its general connection symptoms.[3] If you can open an experience in Build or Edit mode but not in Play mode, that is a classic connection problem rather than a broken install.[3]
First Check Whether Roblox Is Down
Roblox runs a public status page at status.roblox.com. It reports each component separately, including Website, Mobile App, Xbox App, Games, Studio, Game Join and Marketplace, and it keeps a 30-day incident history.[4] When the Game Join component is degraded, you cannot join anything and the error looks like it came from your computer.
Recent history on that page is useful context. Roblox logged a degraded performance incident on October 5, 2026 affecting the User, Player and Creator components, which it identified at 16:04 PDT and resolved at 16:13 PDT, and a separate Studio publish disruption on September 28, 2026 that ran from 16:05 to 19:18 PDT.[4]
Third-party trackers see the same pattern. Downdetector's Roblox page reports the most common problems as server connection, game launch and game play.[6] DownForEveryoneOrJustMe records the same October 5, 2026 outage at about 47 minutes, and notes that launching the game is the single most reported Roblox problem across its data.[7]
So before you touch a firewall setting, open the status page. If everything reads Operational and you still cannot connect, the problem is almost certainly on your side of the router.[4]
The Port Range That Gets Blocked
Roblox does not use one fixed outgoing port. The client scans for a free port on your machine and assigns ports dynamically for each experience session.[9] Roblox publishes the range it expects to be available as UDP 49152 to 65535.[3][8]
That range matters more than most guides admit. Because the client picks a port at random inside it, blocking a single port number often does nothing, while blocking the whole range breaks every join attempt. If your router blocks UDP packets on any port in that span, Roblox will not connect.[9] Roblox recommends contacting your ISP if the ports need to be opened or activated on the router.[8]
Fix Order: Roblox's Own Steps
- Try a different internet source. Roblox lists this first for both 277 and 279. Switch to a phone hotspot or another network and see if the error follows you. If it does, the issue is local to your machine rather than the connection.[1][2]
- Check the official status page. A degraded component explains the error without any fix on your end.[4]
- Reinstall Roblox. Roblox says a fresh copy clears corrupted files and data that affect how the application runs, and updates it to the latest version.[1][2]
- Clear the local app data. On Windows, uninstall Roblox, open a command prompt, run [c]cd AppData\Local[/c] then [c]rmdir /s Roblox[/c], confirm with [c]y[/c], restart, and reinstall.[1] On Mac, open Privacy & Security settings and make sure Roblox has permission to run.[2]
- Correct the date and time. Roblox lists this for iOS, Android and Fire OS. Wrong clock settings stop the system staying in sync with the servers.[1][2]
- Use a supported browser. If you play in a browser, Roblox names Microsoft Edge, Firefox and Chrome, and asks you to try a different one if the current browser will not load an experience.[3]
- Remove ad-blockers and browser extensions. Roblox calls this out directly, saying ad-blockers can stop an experience from fully loading.[3]
- Open the UDP port range on your router. UDP 49152 to 65535, with your ISP if the router needs it.[3][8]
- Allow Roblox through the firewall. Add Roblox to the program permissions list and give it unrestricted access.[3][9]
- Fix antivirus false positives. Update the antivirus first, then add Roblox to the exceptions list. On Windows the Roblox files live in [c]C:\Users\(Your Windows Username)\AppData\Local\Roblox[/c].[8]
- Look for third-party programs. Roblox names auto-clickers and other game launchers as examples of programs that can hinder the client's connection or functionality.[8]
- Contact Roblox support. If nothing above works, Roblox asks for your username, the error messages you received, your device model, your OS version and the steps that lead to the issue.[3]
| Platform | Steps Roblox lists first | Notes |
| Windows 10 and 11 | Reinstall, clear AppData, check network source | Uninstall through Settings or Control Panel, then reinstall from the official download page[1][2] |
| macOS 10.13 and above | Delete the app, check Privacy & Security permission, check network source | Roblox asks you to confirm the app has permission to run[2] |
| iOS 12 and above | Reboot the device, force close the app, reinstall | Then check that the date and time are accurate[1] |
| Android 6 and above | Reboot the device, force close the app, reinstall | Then check that the date and time are accurate[2] |
| ChromeOS 53 and above | Update ChromeOS, force close the app, reboot, reinstall | Roblox links to Google's own ChromeOS update instructions[1] |
| Amazon Fire OS | Force close the app, reboot the device, reinstall | Roblox lists supported Fire 7, HD 8, HD 10 and Max 11 generations[2] |
Roblox's reinstall guidance is more specific than most guides suggest. On Windows you usually do not need to uninstall first, because the reinstall overwrites deleted or broken files. If reinstalling does not work, uninstall, restart the computer, then reinstall. Roblox also asks you to delete your browser's temporary internet files and cookies, and to make sure every other program is closed during the install.[10]
On Mac, the flow is different. Quit Roblox completely, uninstall, then open Safari, log in and start playing. The installer prompt should appear. If it does not, go to Finder, open Today, and click Roblox.dmg to run the installer.[10]
Other Roblox Error Codes Worth Knowing
Roblox keeps a master index of error codes, and it is the fastest way to identify a code you have not seen before. The index covers 264, 266, 267, 268, 270, 277, 279 and ID 17, 280, 403, 524, 600, plus "Failed to Load Library".[5]
Two of those are easy to confuse with connection problems. Error code 280 says your version of Roblox may be out of date and asks you to update, which is a different fix from 277 or 279.[5] Error code 403 means access to the page was denied and you are not authorised to view it.[5] If your code is not in that index at all, Roblox asks you to contact its support team.[5]
FAQ
Why do I keep getting error code 277 in Roblox?
Because the client lost its network connection to the game server mid-session.[1] Roblox's own first-line fixes are reinstalling the application, clearing the local app data, and trying a different internet source.[1] If the error follows you onto a different network, the cause is on your machine rather than your connection.
How do I fix error code 279 on Roblox?
Start with the status page, then try a different internet source, then reinstall Roblox and clear the app data, then check the date and time.[2] If you play in a browser, switch to Edge, Firefox or Chrome and remove any ad-blockers, which Roblox says can stop an experience loading.[3]
Does Roblox error 277 mean my account is banned?
No. Error 277 is a network error, not a moderation action. Roblox defines it as a lost connection to the game server, and the fix list is entirely about network access, corrupted files and clock settings.[1] If the account itself were the problem you would see a different message.
What ports does Roblox use?
Roblox says the port range is UDP 49152 to 65535, and the ports the client uses depend on the operating system.[3][8] The client scans for a free port on your machine and assigns them dynamically per session, so blocking any UDP port in that range can break joins.[9]
How do I check if Roblox is down right now?
Open status.roblox.com, which reports each component separately and keeps a 30-day incident history.[4] Cross-check with Downdetector, which lists the most common Roblox problems as server connection, game launch and game play.[6]
My antivirus flagged Roblox. Is Roblox safe?
Roblox addresses this directly in its third-party applications article, telling users to flag the warning as a false positive and add Roblox to the antivirus exceptions list.[8] On Windows the Roblox files sit in [c]C:\Users\(Your Windows Username)\AppData\Local\Roblox[/c].[8] Only add the exclusion if you installed Roblox from the official site.
Sources
- Roblox Support: Error Code 277 - Lost connection to the game server
- Roblox Support: Error Code 279/ID 17 - Failed to connect to the Game
- Roblox Support: General Connection Problems
- Roblox Status - official system status page and 30-day incident history
- Roblox Support: Roblox Error Codes index
- Downdetector: Roblox outage reports and most reported problems
- DownForEveryoneOrJustMe: Roblox outage history and common problems
- Roblox Support: Third party Applications or Antivirus Software Restrictions
- Roblox Support: Firewall and Router Issues
- Roblox Support: How Do I Reinstall the Roblox Software?