When applying for a server auth key I entered the incorrect IP address. I need to either edit or delete this key so I can redo it with the correct address.
Read this carefully: https://wiki.beamng-mp.com/en/home/Server_Mod
You may have missed a step.
Okay, I have done this but I cannot connect to the server.
The IP you used doesn’t matter at the moment. Continue with the server set up as if you put the correct one.