Your ip doesn't match one of the allowed ips for this account

See title… can’t log onto my reborn account on the client cause I’m ujsiong a different ip addrtess.

Happens when you’re set as staff on a server and your current IP address does not match the range that was set for your account.
It’s ... by default, which is considered insecure, since anyone with your ingame password would have the same access rights as you.

Long story short, your IP address has changed and is no longer within the accepted range you put.
You will need someone with access to your server with the ability to modify account rights to change your range

If you’re hosting your own server you can shut it down and edit your account file in notepad and change the IP range back to ... till you find the appropriate range(s).
If you’re hosting on Joey’s server, back up your server, Delete the server. Create a new server. Upload old content.