Still cannot send mail via apple mail

This problem started suddenly and I have talked with Comcast’s support, they blamed apple, talked with apple they blamed comcast.  What a surprise.  I am paying for service I am not getting.  I have spent hours trying to fix the problem, using every suggestion giving to me by the support people.  They couldn’t fix the problem so they blamed each other.  This isn’t the first time I have had an issue with Comcast’s email.  Maybe it is time to take my money elsewhere.