"You are not allowed to send email" when using exim-sender

[ensonic]

This is most likely a user error, but having more info in the readme would be helpful. This is what I am doing.

# using mydomain.de as an example below
# IP is the external ip the domain points to
docker run -p 4444:25 -v /tmp/exim:/var/spool/exim4 -e PRIMARY_HOST=mydomain.de -e ALLOWED_HOSTS="$IP" elsdoerfer/exim-sender

in a 2nd terminal I run

telnet localhost 4444
Trying ::1...
Connected to localhost.localdomain.
Escape character is '^]'.
220 mydomain.de ESMTP Exim 4.82 Ubuntu Sat, 02 Jun 2018 14:09:24 +0000
mail from:$USER@mydomain.de
250 OK
rcpt to:foobar@gmail.com
550 "You are not allowed to send email"
quit

The same happend when I connect with telnet through the external interface.

[beldaz]

I get a very similar problem sending emails from Flask-Mail from another container.