Roblox error codes 277 and 901 disrupt gameplay by disconnecting users from servers or blocking login attempts. Error 277 typically signals lost connection to the game server, while error 901 points to authentication problems. Both errors can result from unstable networks, corrupted application files, or account issues. Addressing these problems involves a mix of network troubleshooting, application maintenance, and sometimes account management.

Fixing Roblox Error 277: Lost Connection to Game Server

Unstable network connections, corrupted logs, or outdated application files are the most frequent causes of error 277 on Windows 11. Addressing these issues restores server connectivity and allows uninterrupted gameplay.

Reinstall Roblox Application

Step 1: Remove the current Roblox installation to eliminate corrupted or outdated files. Open the Windows search bar and type Control Panel. Select Programs, then Programs and Features. Locate Roblox in the list, right-click, and choose Uninstall. Follow the on-screen prompts to complete removal.

Step 2: Visit the official Roblox download page and download the latest installer. Run the installer to set up a fresh copy of Roblox, ensuring all files are current and intact.

Clear Roblox Log and Configuration Files

Corrupted logs or configuration files can prevent Roblox from maintaining a stable server connection. Removing these files forces Roblox to generate new, error-free versions.

Step 1: Ensure Roblox is fully closed. Open File Explorer and paste %LocalAppData%\Roblox into the address bar. Press Enter to navigate to the folder.

Step 2: Find the file named GlobalBasicSettings_13.xml (or just GlobalBasicSettings_13). Right-click and delete this file.

Step 3: Open the logs folder within the same directory. Select all files inside by pressing Ctrl + A, then press Delete. Do not delete the folder itself, just its contents.

Step 4: Optionally, clear additional log files by opening the Run dialog (Win + R), entering %USERPROFILE%\AppData\LocalLow\RbxLogs\, and deleting all files in that folder.

Switch to a Different Network Connection

Network instability or restrictive router settings can disrupt Roblox’s ability to connect to its servers. Testing with another connection isolates whether your current network is the source of the problem.

Step 1: Disconnect your PC from your current Wi-Fi or wired connection. If possible, use another available network—such as a mobile hotspot or a different Wi-Fi router—to connect your device.

Step 2: Launch Roblox and attempt to join a game. If the error disappears, your original network may be blocking required ports or experiencing intermittent outages. Contact your ISP or adjust router settings (such as opening UDP ports 49152–65535) if necessary.

Run Roblox in Compatibility Mode

Compatibility issues between Roblox and Windows 11 can cause connectivity problems. Running Roblox in compatibility mode can resolve these mismatches.

Step 1: Right-click the Roblox shortcut or executable file and select Properties.

Step 2: Go to the Compatibility tab. Check Run this program in compatibility mode for and select Windows 7 or Windows 10 from the dropdown list.

Step 3: Click Apply and OK to save changes. Start Roblox and check if the error is resolved.

Update Web Browser and Disable Extensions

Outdated browsers or conflicting extensions can block Roblox’s web-based features. Keeping your browser current and disabling unnecessary add-ons reduces potential conflicts.

Step 1: Open your browser’s settings menu. In Google Chrome, click the three dots in the upper right, select Help, then About Google Chrome. Chrome will check for updates and install them automatically.

Step 2: Disable browser extensions by navigating to the extensions menu and toggling off unnecessary add-ons. Restart the browser and try launching Roblox again.

Reset Network Adapter and Flush DNS

Network adapter issues or a corrupted DNS cache can disrupt Roblox’s ability to connect to servers. Resetting these components often restores connectivity.

Step 1: Open Command Prompt as administrator by searching for cmd, right-clicking, and selecting Run as administrator.

Step 2: To flush the DNS cache, enter:

ipconfig /flushdns

This command clears outdated or corrupted DNS records.

Step 3: To reset the network adapter, enter:

netsh int ip reset

Restart your PC after running these commands, then test Roblox again.

Fixing Roblox Error 901: Authentication Error

Error 901 typically signals problems with account authentication or communication with Roblox servers. This error appears during login attempts and may be related to account bans, temporary glitches, or corrupted application data.

Check Account Status

Step 1: Visit the official Roblox login page and attempt to log in. If you cannot access your account, it may be banned or suspended.

Step 2: If you suspect a ban, contact Roblox support to verify your account status and, if applicable, appeal the ban.

Sign Out and Re-Authenticate

Temporary authentication glitches can be resolved by signing out and signing back in, which resets your session and clears cached credentials.

Step 1: Open Roblox and log out of your account.

Step 2: Close the application completely, then reopen it and sign in again using your credentials.

Step 3: If using a linked Xbox account, unlink and relink the account through the settings menu to refresh the authentication token.

Reinstall Roblox Application

Corrupted or incomplete installations can cause persistent authentication errors. Reinstalling ensures a clean set of application files.

Step 1: Uninstall Roblox from your PC using Control Panel > Programs > Programs and Features. Select Roblox and click Uninstall.

Step 2: Download the latest version from the official Roblox site and install it.

Try a Different Platform or Device

If the error persists on one device, but not another, the problem may be device-specific. Test your account on another PC, mobile device, or web browser to determine if the issue is isolated.

Step 1: Log in to Roblox on a different platform. If authentication succeeds, your original device may have lingering configuration or cache issues that require further troubleshooting.

Contact Roblox Support

If none of the above methods resolve error 901, reach out to Roblox’s official support team. Provide detailed information about your account, device, and the error message to expedite assistance.

Addressing Roblox errors 277 and 901 on Windows 11 requires a combination of network troubleshooting, application maintenance, and account checks. Following these steps restores reliable access to Roblox and minimizes future disruptions.