If you are getting this error message when you attempt to log into Parallels, see this solution.
Logging in via Parallels Client on your Desktop
Step 1: Open Parallels Client on your desktop
Step 2. In the panel on the left-hand-side under the heading 'Connections', right click on your connection and select connection properties.
Step 3. The connection properties will open. Change the Port Number (see highlighted below) from 443 that it is currently to 444.
Step 4. Connect to Parallels again and you will be able to log in as normal.
Logging in via the Web Browser
Please access Parallels via this website from now on: https://chintarocloud.com.au:444/RASHTML5Gateway/#/login