Q: Can't Connect to iMessage or Facetime

Up until yesterday I could connect to iMessage or Facetime on my MacPro (Later 2013).

Running 10.11.6 software. Everything has been working fine up until yesterday. Now, it will not let me connect! I can get on iCloud and everything else. 

Wondering if any one else was having this problem?

Been reading though, and it seems that you have to call Apple and get them to re-set your Apple ID and Password on their server.

Is this true???

Thanks for any help.