An addition...
There was a preview domain before the server was changed,
so you could see how the new server is working
before the main domain was linked to it.
Currently the preview domain is still available
( like
http://<my_own_domain>.de.preview.<provider_domain>.de )
I tested with replacing the the donain with preview domain again,
and it works.
I went to the Admin section, and changed both URL input boxes to the real domain -
i can not login again
( so it is not possible that i messed up something with config files,
i used admin section of the forum to change configuration )
I have access to everything in Forum, just as anonymous user,
by clicking on any link after logging in ( and being in "Home" ),
i'm not logged in anymore !
....................
I'm in office, here i can log in, no problems,
so may be somehow i did not deleted all cookies ?
I sorted them for date...
But anyway, it is not so good solution to tell users
"delete all your cookies" or "try to find and delete all cookies regarding my forum"...
Is there any way to fix it on the server side ?
( withoult asking users to delete thier cookies )