Check your antivirus is up to date.
Check your SBCGlobal email account is set up correctly.
Instead of using a POP account, use IMAP.
Your email profile should be deleted.
In Outlook, go into safe mode.
Consider using Google DNS.
Use webmail or a separate email client.
Read more here:- https://www.datarecovo.com/sbcglobal-email-not-working-with-outlook/