If RoVer says "User is banned", that means that the Roblox account that's linked to your Discord account is listed in the Discord server's Roblox Bans list.

Either the server owners manually issued a ban on your Roblox account, or you were banned from the server on another Discord account.

If the server owners are trying to unban you, and you are still getting the "User is banned" response, check the following:

• The server owners should double check that your Roblox account doesn't appear in the Roblox Bans section in the server dashboard.
• Allow up to one full minute after the Roblox Ban has been removed before attempting to rejoin.
• Ensure that you do not have any alternate Discord accounts that are also banned in the server. If you do, the server owners will need to unban those accounts as well.

See also: Banned from a Roblox game?