To login to Plesk control page in Internet Explorer please use the following steps:-
1) Enter your domain name in the Internet explorer web browser. The control panel
works on port 8443 with https so you need to enter the URL like this :-
https://your_domain_name.com:8443
(Replace your_domain_name with your domain name)
2) The SSL certificate popup window will open. Click on "Yes" as it will ask "Do you
want to proceed". Once you enter the "Yes" button the Plesk control panel will open.
