Postfix: irregular denial of relay of incoming mail

Pioneer Support
1

Hi,

My FreedoBox is plugged into a router at home. I got the kit in September 2023 but just set it up last week. Today, version 25.15 running on Debian 13. Running on domain windytilleuls.com

Apps enabled: Bepasty, Cockpit, ejabberd, Cotern, Postfix/Dovecot, SOGo.

They all seem to be working perfectly. No errors in Cockpit.

Problem: When I send an email from my usual email providers (I test with 3 different providers) to my email account on Freedombox (admin@windytilleuls.com), from time to time my Freedombox email inbox receives it (both with SOGo and with Thunderbird), but usually my Freedombox email does not receive it.
Instead I get in the inbox of the mail of the account I sent the mail from a “returned mail” message with the following error:

“<<< 554 5.7.1 admin@windytilleuls.com: Relay access denied 554 5.0.0 Service unavailable <<< 554 5.5.1 Error: no valid recipients”

When I say “from time to time” I get the mail, intuitively it is about 5% of the time and usually it is just after I changed something in Postfix’s smtp relay restrictions in main.cf (but that could be a coincidence)

I haven’t identified a pattern in the errors, reloading Postfix usually doesn’t change anything but sometimes an email goes through immediately after a reload but the following email are then rejected.

Could someone help me in any way in approaching this issue?
thanks

2

Generally, the FreedmBox mail server should run out of the box. For learning purposes I did install the email server many times and I run the Postfix/Dovecot app for my families main mail address since one and a half year with no problems except some errors, which do not affect the mail servers functionality. Since there is SOGo available on FBX, I run SOGo and this app works great together with the email app. I’m still a newbie, but I think you shouldn’t touch Postfix’s smtp relay restrictions in main.cf.
You should receive the emails from outside. Question: does your provider accept a private email server? Some ISPs do not. Test it with nc freedombox.org 25 in your cockpit terminal.
Under yourdomain/plinth/help/manual/en/Email you will find information about this.