E-mail from domain imap.comcast.net not displayed on iphone 10
About a week ago all of my old e-mails from my comcast account disappeared from my iphone 10. I have:
Installed all iphone updates
Changed my password
Updated password on my iphone
New messages are displayed but, once read, they disappear from my inbox. I always use these to refer back to and would like them to be displayed. What do I need to do?