Cannot get IMAP working in Docker

[edleeman17]

HI,

I'm unable to get IMAP working inside docker. At the moment I am using docker exec to run the bundle exec rake helpy:mailman mail_interval=60& command. (No idea how to run this as default.)

It appears that when I receive an email, I get the following error.

I've noticed that a few people are also having the same issue in #936

Thanks