I'm running the image with SMTP_ONLY=1 and PERMIT_DOCKER=network. For months now, I have successfully sent email from other docker containers, no problem. External sending was not possible and there were no "emails" configured (as understood by the setup.sh script), only a few aliases.

Now I'm trying to enable sending for a single external account, so that an app running on a different machine can use the server. So I added an "email" account and set a password:

./setup.sh email add [email protected]
./setup.sh email restrict add receive [email protected]

I have since restarted the container (I think that might be important). I can also see the newly created account in postfix-accounts.cf.

However, when the external machine tries to deliver mail to the server, I see this error (on the side of the client):

5.5.1 Error: authentication not enabled

The server logs show one interesting line: apparently /etc/postfix/vmailbox can't be opened. Not sure what that means though.

Sep  2 12:57:06 mx postfix/smtpd[4855]: error: open database /etc/postfix/vmailbox: No such file or directory
Sep  2 12:57:06 mx postfix/smtpd[4855]: connect from <my sending server>[<myip>]
Sep  2 12:57:06 mx postfix/smtpd[4855]: Anonymous TLS connection established from <my sending server>[<myip>]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Sep  2 12:57:06 mx postfix/smtpd[4855]: lost connection after AUTH from <my sending server>[<myip>]
Sep  2 12:57:06 mx postfix/smtpd[4855]: disconnect from <my sending server>[<myip>] ehlo=2 starttls=1 auth=0/1 commands=3/4

Am I missing something here? Do I need to do something else to make the server accept the login attempt?