Help with installing Mo Creatures mod on server?

I've been trying to get mo creatures to work on my server. I can get the server up, but I can't connect to it with forge or the regular client. Can anyone help?

I've set my Server to 1.12.1 as forge seems to stick with 1.12.1 and i enabled crack server, although im not sure if that helps at all. I get the FML mod rejected message for both more creatures and custom creature spawns.

Quote from Roman

check if you have the same version of the mod installed on your client as on your server.

Thank you, that might just be it, heres to hoping