WSUS not working properly with SSL

I have removed the server and tried to re-add it with it's Public name. I have also checked the SSL Box (using port 8531), but getting the error:

Cannot Connect to 'UPDATE.DOMAIN.COM'. Please make sure the Post-Installation task is completed successfully in that server. If it was, please verify if the server is using another port og different Secure Sockets Layer (SSL) setting.