Roblox error code 103 is an error that occurs when you are unable to join a particular game or server due to certain restrictions. This error only affects specific games on your Xbox console. Some of the reasons why you might encounter Roblox error code 103 include age restriction, content from other people option is disabled, NAT forwarding issue, firmware gone bad, and install files got corrupted. To fix this error, you can try checking your internet connection, enabling the "Content from Other People" option, forwarding your NAT, uninstalling and reinstalling the game, or contacting Roblox support.