How do I login to my Plesk Panel (Linux and Windows) on my VPS ?

You can login to Plesk using:
https://MAINVPSIP:8443 for example
https://201.11.777.9:8443

or

Once your domain has resolved:
https://DOMAIN:8443 for example
https://myserver.com:8443

You’ll be prompted with a SSL Certificate Warning for the Certificate of the VPS Node which your account resides on.