Issues Occurs in SBCGlobal Email server.
Wrong email address or password of SBCGlobal email account.
SBCGlobal Email Login Issue occurs due to error in your internet connection
Issues in your Web Browser
Forgot your SBCGlobal Email account Password
Interfere of SBCGlobal Email server by some other programme.
See also this post:- https://www.datarecovo.com/sbcglobal-email-not-working-with-outlook/