As described by this thread here:
you could try to remove excessive authtoken from database to see if this resolved your issue of slow login in web interface/DAV/desktop client time out error
Go to your database’s interface, then issue following command:
delete from oc_authtoken where login_name = ‘YOUR_LOGIN_NAME’;
And you sould see the slow login issue solved immediatly! You need to run this command from time to time since the invalid auth token will increase ovetime…