Wrong User ID or Password. Slow Internet Speed or error in internet. Error in your Web browser. SBCGlobal Email password may be forgot. Interfere of Server of SBCGlobal Email with third party software. SBCGlobal Email sever may be down. 
Above given are the best reasons for SBCGlobal Email Login Issues. 
See Also this post:- https://datarecovo.puzl.com/_news/How-do-I-Log-into-My-SBCGlobal-net-Email%253F/301993 https://datarecovo.hpage.com/how-to-fix-sbcglobal-email-login-problems.html
