said by Lorob:My mail servers are sbcglobal.yahoo.com but when signing on to the servers the certificate is issued to att.yahoo.com. I'm using ports 995 and 587. And yes, it is an SSL connection.
Both 'smtp.sbcglobal.yahoo.com' and 'pop.sbcglobal.yahoo.com' have been deprecated for years; nearly five years. AT&T announced, around March, 2008, that the new server names to use should be, 'smtp.att.yahoo.com' and 'pop.att.yahoo.com'. The AT&T recommended SMTP port to use is 465.