Solved NextCloud Email client cannot be setup.

[Beryllium]

When trying to setup the NextCloud email client, the process fails with the following error:

Error while creating the account: Creating account failed: Server does not support TLS connections.

In manual configuration IMAP host is set to port 993 with SSL/TLS and SMTP is set to port 587 with STARTTLS as per documentation.

On the server, both ports 993 and 587 are open with netstat output

tcp6 0 0 :::993 :::* LISTEN
tcp6 0 0 :::587 :::* LISTEN

In reveiwing the issue, I discovered NextCloud doesn't support any thing but TLS1, does Cloudron only use TLS1.2?

[Beryllium]

I overlooked the closed tickets on Cloudron's NextCloud git repo. Setting the SMTP server to port 25 without encryption solved the issue as per the suggestion in this thread.

[girish]

Also, it is safe to disable encryption since the communication is internal to the VM.

[girish]

In case, you find this post by search, there is doc on how to set this up here - https://cloudron.io/documentation/apps/nextcloud/#email