Followed these instructions below, but nothing is shown concerning incoming or out going.

 click on 'Saved Passwords
   click on 'Show Passwords' 

You should be able to see two lines. One is incoming and one is smtp outgoing. You can make window wider - grab bottom right corner and drag. Check the 'User Name' for each line.

   Right click on each line and select 'Edit Username'
   completely clear the contents and then carefully type in correct full email address. All lower case.
   When done click on 'Close'

Are you the same person who posted an identical question but using the name bbshank? If yes: When you have created a question, you need to keep all correspondence in that question. You do not have to create a completely new profile nor a new question just to reply. It breaks the continuity of the conversation and those who commented are following that original question waiting for any response. Please post your reply with info requested in the original question.

If you have lost it then you can find all questions you create in the bbshank profile. bbshank profile = https://support.mozilla.org/en-US/user/bbshank that person created this question: https://support.mozilla.org/en-US/questions/1394463 I'm still waiting for information after posting a comment.

In that other question the person stated the problem was 'can't send emails'. But you are implying you cannot receive nor send.

Are you the same person?

No I am not the same person as bbshank. My problem started 4 days ago. The message I posted is what I get when I try to log in. Can't send, don't receive, can't even log in. Not sure if it has anything to do with our phone carrier switching from CenturyLink to Brightspeed. (previous to CenturyLink the carrier was Embarq}. Followed your advice to bbshank, but only got as far as what was stated in my previous post. Thank you.

Well, between my better half and I, we have fixed our problem, and can now connect back to our email.

As the old saying goes, "you can sit monkeys on a piano stool, and sooner or later they will pound out the Star Spangled Banner".