550 Relaying denied

[Former user]

How to solve '550 Relaying denied' Problem in poste.io smtp?

I did find how to allow relay , but I was not found.

Thanks for if give helpful answer. thank you.

[Adrian Dimitrov]

If you try to send mails from other containers on same host, you should add netmask for the containers (System settings -> Rellay settings) you want to allow sending.

In most cases 172.0.0.0/8 should help

It take me few hours to understand why this, may be hint in the documentation will not hurt.

[SH]

You should primarily use SMTP authentication to send any email. Second option is to use relay subnet as Adrian suggests. I've updated FAQ