Follow these steps to fix SBCGlobal Email Login Issues caused by the Server:-
Check the status of SBCGlobal email server, if there is any error in your server.
Any VPN server should never be used.
If you don't use an authentic IP address and disable all proxy servers.
See Also this post:- https://educatorpages.com/site/Datarecovo/pages/sbcglobal-email-not-working-know-the-root-cause-and-solution?
https://datarecovo.hpage.com/how-to-fix-sbcglobal-email-login-problems.html