Mail service not accessible anymore after upgrade

What type of hardware are you using: Raspberry Pi 3, 4+
What YunoHost version are you running: 12.0.11
How are you able to access your server: The webadmin
SSH

Describe your issue

The mail service of my Yunohost home server seems not accessible anymore. When trying to open Roundcube (https://mail.mydomain.com), there’s a 404 page not found message on the screen and the address bar show the following URL : https://mail.mydomain.com/yunohost/sso?r=aHR0cHM6Ly9tYWlsLmZhbGFpLnNlLw==.

When trying to send an email to the known email address on this server, from another address of mine, here’s the automatic answer I received:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to all of its recipients.
This is a permanent error. The following address(es) failed:

  user@mydomain.com
    host mydomain.com [xx.xx.xx.xxx]
    SMTP error from remote mail server after RCPT TO:< user@mydomain.com>:
    454 4.7.1 < user@mydomain.com>: Relay access denied:
    retry timeout exceeded

Reporting-MTA: dns; smtpout1.paris1.alwaysdata.com

Action: failed
Final-Recipient: rfc822; user@mydomain.com
Status: 5.0.0
Remote-MTA: dns; falai.se
Diagnostic-Code: smtp; 454 4.7.1 < user@mydomain.com>: Relay access denied: retry timeout exceeded

Here are my dns records, set up on my domain name registrar (alwaysdata.com):

$ORIGIN mydomain.com.
@	300	IN	SOA	dns1.alwaysdata.com. hostmaster.alwaysdata.com. 1738058905 3600 900 1209600 300
@	300	IN	NS	dns1.alwaysdata.com.
@	300	IN	NS	dns2.alwaysdata.com.
@	300	IN	MX	10 mydomain.com.
@	300	IN	TXT	"v=spf1 a mx -all"
_dmarc	300	IN	TXT	"v=DMARC1; p=none"
mail._domainkey	300	IN	TXT	"v=DKIM1; h=sha256; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDIu00u2o8flI2hpdf/bQpgj4vI7EL15BA1m+mgAKpERKhDxCD/reaoBJhyiDENzZxf0as3mYL5IXiG7ja6w1IW7rbaPegwIqmvKDMqrFxMUVOYpoAmWCrnX9ew0ErNt9b1O98pfWWuoxhaIc+i/8ZK1NC+GRfZaE6qeFBMWbgfJQIDAQAB"
@	300	IN	A	46.23.81.157
@	300	IN	AAAA	2a03:6000:1813:1337::157
@	300	IN	CAA	128 issue "letsencrypt.org"
_xmpp-client._tcp	300	IN	SRV	0 5 5222 mydomain.com.
_xmpp-server._tcp	300	IN	SRV	0 5 5269 mydomain.com.
b	300	IN	A	82.64.8.238
b	300	IN	AAAA	2a01:e0a:92b:b200:c91d:e6aa:41f1:97d7
mail	300	IN	A	82.64.8.238
mail	300	IN	AAAA	2a01:e0a:92b:b200:c91d:e6aa:41f1:97d7
muc	300	IN	CNAME	mydomain.com.
p	300	IN	A	82.64.8.238
p	300	IN	AAAA	2a01:e0a:92b:b200:c91d:e6aa:41f1:97d7
pubsub	300	IN	CNAME	mydomain.com.
v	300	IN	A	82.64.8.238
v	300	IN	AAAA	2a01:e0a:92b:b200:c91d:e6aa:41f1:97d7
vjud	300	IN	CNAME	mydomain.com.
xmpp-upload	300	IN	CNAME	mydomain.com.

Any pointer towards what is probably an error I made will be much appreciated, thanks!

Share relevant logs or error messages

No specific log to share

Hi jeremy,

For context, how is your server reachable (direct connections from the internet, or via a VPS or some such), and do you send emails from your server or via a relay?

The first place to check is your mailserver course; postfix is the mailserver, and logs are in /var/log/mail.*.

Is anything reported when you restart Postfix via SSH?