Yes, you can't use the multiple domains at the same time. It sees those as different cookies.
You need to use the same URL consistantly.
If a user logs in at smygis.com (without the www) they can login and get a cookie for that domain.... then when they click a link, they will probably be taken to
www.smygis.com (or forum.smygis.com) and thus they aren't logged in there. Then everything get's confused at that point.

One click they are logged in, another they are not.
I tried to run .com and .net of my domain at the same time during a server move. Bad idea.

I ended up setting up .net to forward to .com. Because people couldn't stay logged in.
Cookiepal will only check for the cookies set by your domain (as defined in your config file). They will need to manually delete the cookies from the other domain. See my "Delete Cookies" doc in the how-to/library forum here.
Whatever domain you define in the config file... stick with it and make sure everyone uses the same to login etc.
People who are having trouble... tell them to go to the logout.php script like this:
http://www.yourcorrectdomain.com/ubbthreads/logout.phpAnd login again.
Hope those tips help.
