Just a quick post today. We have migrated our Symantec Endpoint Protection Manager to a new server last week. For the most part the Disaster recovery best practices support article is very useful. However what it doesn’t mention is that unless your new server has the same name your clients will still be trying to connect to the old one. I suppose that’s why it is a DR procedure rather than a migration.
What you need to do is update the clients connection settings. There are a few ways in which you can achieve this again pretty well detailed here and for SEP 12.1 RU2 or newer here.
What Kat Did 
I just finished a migration from one VM host to another. The SEP server could not be moved due to a “punctured raid disk”. So, I created a new SEP server, and migrated the old AV settings over using Symantec’s DR procedures. Everything went well with the exception of the Admin password. That is how I found this blog. Google led me to your past post, which had the original (and now retired) password reset batch file. It worked like a charm.