The problem has been solved. It seemed that my website is known as “http://www.mysite.com” in stead of “http://mysite.com”. Because I logged in on mysite.com/login.php it threw a 403 error.
PS I used “mysite”, which doesn’t refer to the real “mysite” site. It’s just an example.
@oskyboy: did you make a backup of your installation and database before you upgraded to WP 3.2.1? I’ve tested a theme, upgraded to WP3.1.2 and after that, the dashboard was “broken”. I switched to the Twenty Ten theme and some other themes, but it didn’t solve the problem. I guess an upgrade can also overwrite or conflict with a part of the existing code. I hope you made a backup and are able to rollback or do a clean install.
The plugin Social Discussions caused it, in my case.
Thank you so much for the information. I’ll try it and see if this solves the problem.
