I was finally able to get this fixed with the help of the following link: On your server: create a self-signed SSL Certificate with SubjectAltName(SAN) https://gist.github.com/KeithYeh/bb07cadd23645a6a62509b1ec8986bbc Once you do that, point your imap server (dovecot in my case) to that new cert. Then, email the cert file to yourself, open it in your phone, and download it. On your phone, open the Files app and find the file. When you open it, you'll be asked if you want to install. Go ahead and do that. It will say something like "View Profile in Settings" so open Settings; you should see it there, click it and follow the instructions. You should then see the cert in the Settings -> About -> Certificate Trust Settings area. For me, I had to restart my phone to see the toggle switch to enable full trust for root certificates. Finally, I was able to get my email! Hooray!