Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
Pop3 and imap mail issues are my specialty. Im certain I can help you fix this. But first, I need to ask you for more info.
The device that is having the issue, is it a mac, an iphone, an ipad?
If its a mac, what version of mac osx are you using? You can check as follows.
Click the apple sign at the top left of your screen, then click about this mac. And then where it says version, send that to me as a reply.
Thank you for your response,