Yahoo Migration-Archive Emails and Comcast Password Question

I accepted the migration yesterday, was prompted by yahoo to select a new password, and the yahoo email worked immediately to send and receive on my apple mail, so that part went fine. 

what did not migrate over were my archived Comcast emails, many of which are very important so I don’t want to do anything that could risk them going away 

what is irritating is that whenever I check email, I get a prompt that my Comcast email password is incorrect. I am still getting emails via yahoo just fine, but I have keep cancelling the prompt. This occurs on all of my apple devices

I would just delete Comcast as an email account but as noted above I can’t do that since my archived emails did not migrate as expected. Should I change my Comcast email password to my new yahoo password? Or is there another approach?

thank you