You may find that you are unable to log in to Plesk due to another login session already being open. This can happen if you close your browser window instead of logging out. The default session timeout is 20 minutes.

To resolve this issue, it is best to allow multiple login sessions:

1. Log in to Plesk
   
   
2. Once logged in, click the ‘Home’ button in the left navigation frame.
   
   
3. Click on the ‘Domain Administrator’ button.
   
   
4. In the Preferences section, check the box next to ‘Allow multiple sessions’.
   
   
5. Click the ‘OK’ button to save.

You should now be able to have multiple login sessions open.