Error 404 when logging

Hi, I have trouble with logging to my WordPress site. I am using wpdirauth plugin for LDAP and I am using SSL to connect with the Active Directory server for user authentyphication.
Currently I get 404 error (page not found) when try logging on to my site. The logs are showing that the path the server is looking for is wrong – it is looking wp-login.php in wrong directory. It looks like the rewrite roules were crashed somehow, but I have tried the .htaccess refreshing, permalinks and nothing helped.
Any ideas will be much appreciated. Thanks in advance.