Issue connecting N8N to IMAP account

[OneWheelGeek]

I'm trying to setup an IMAP trigger in N8N using a mail account on my Cloudron machine.

In Cloudron, I've added the new mail account to my user and generated an app password for it (n8n@domain.com).

I've confirmed that I can login via. IMAP remotely from another device:

server: my.erratic.cloud
port: 993
username: n8n@erratic.cloud
password: [app password]

Now, in N8N I've added a new set of IMAP account credentials:

user: n8n@domain.com
password: [app password]
host: my.erratic.cloud
port: 993
SSL/TLS: yes
Self-signed: no

However, any attempt to use/save those credentials is met with a timeout error.

Couldn’t connect with these settings 
Timed out while connecting to server*

Any hints would be appreciated.

[girish]

@OneWheelGeek If you open a n8n web terminal, are you able to telnet my.domain.com 993 ? Does it connect ?

[OneWheelGeek]

@girish I'm just going to hang my head in shame now

This box is behind NAT and, apparently, I'd messed up my firewall rules.

Thank you for the shell/telnet suggestion though. That was helpful.

Sorry for wasting your time!