Roblox error code 279, sometimes shown with ID 17, means the app failed to connect to a game server. The problem may be your connection, a blocked Roblox service or an outage outside your home.
It is a connection error, not proof that you were banned.
Start with Roblox itself
Check status.roblox.com and try joining another game. If many games fail at the same time and Roblox reports an incident, waiting is usually the only useful fix.
One broken game may have a server-side problem even while the rest of Roblox works. Check whether other players are reporting the same thing on the game's official page.
Restart the connection
Close Roblox, restart your device and reconnect to Wi-Fi. If possible, try a stable home connection instead of weak mobile data or a busy public network.
Do not reset the whole router without asking the person who manages it. That disconnects everybody in the house and may not be necessary.
Look for something blocking Roblox
A firewall, security app, VPN, browser extension or school network may block part of the connection. A parent or device owner can check whether Roblox is allowed rather than turning all security off.
Avoid websites offering an error-279 fixer. Roblox does not require a mystery download to repair this code, and fake tools may contain malware or steal your account.