Mail app iwith Docker

Have recently installed Nextcloud as a Docker container using docker-compose file and nginx proxy manager file. Mail app will not connect with imap/smtp servers. I just get a simple message that there was an error, try again later. I see the same problem on X86-64 and Raspberry Pi installs. Have been using the mail app on native installs for some time with no issues. Is there something I need to change or do differently to use with docker and nginx proxy manager?

For me mail app works from docker-compose setup. Nothing special I can remember… The app itself doesn’t satisfy my need but it works!