Problem sending password reset with postfix

[hnpilot]

I have made a Docker installation with this pair of containers which I have got up and running, but I have problems when the sending password reset email.

Server error An error occurred while processing your request.

My configuration is a Centos 8 server. I have made a local installation of nginx and postfix. I got the nginx working OK but get an error with web server sending email.

Is it enough, if I add the SMTP_HOST environment variable (port is 25=default and no authentication) to configure Django to use postfix? I am also wondering what is the right IP for the host? Is it 172.19.199.1, 127.0.0.1 or internal IP of the host (in this case 10.1.26.XXX). I have tried all of them, but nothing seems to work...

Sorry if the questions are dumb - though I have always said that there are no dumb questions, only dumb askers :P - but even after quite many years on the IT there always are new problems and techniques...

wbr

hank