MyBB Community Forums

I think this is not cookies problem. Coz Users can login and stay loged in.

But Users who signup with previous (real) domain they can't log in through the new adon domain. And vice verse.

I can't understand the problem. Hope it is from the setting or some codes can be added.

MyBB allows only one domain to be used.
If you have a previous domain, just make it redirect to your new one, and use the new one as MyBB's domain.

Ok. I makes new one as adon to previous,

And using new as my forum's domain.

Thanks.