Hello everyone,
I have a problem with my aaPanel mail server and I cannot find the cause.
Since 12.11.2025 my PHP Shopware 6 system suddenly stopped sending emails. Before that, everything worked without any issues. From one moment to the next, no email is being sent anymore.
At first I suspected an SSL certificate problem. I renewed the Let’s Encrypt certificate for my domain doitauto.de, but the issue still remains.
This is the error that appears in the logs:
{
"error": "Unable to connect with STARTTLS: stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages:\nerror:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed",
"rawMessage": "Subject: Order confirmation do-it-auto
From: do-it-auto info@doitauto.de
To: ...
}
The aaPanel Mail Server module is running.
All DNS checks (MX, A, SPF, DKIM, DMARC) are green.
Only SMTP sending on port 587 is failing.
I need help to understand the following:
• How to check which SSL certificate the mail server is currently using for STARTTLS
• Where to set the correct certificate path inside the aaPanel Mail Server module
• Whether the mail server is using the correct certificate of the main domain or an old one
• Whether there is any caching or wrong certificate path
• Whether aaPanel assigned the wrong certificate after renewal
I did not change anything in the configuration. The problem appeared out of nowhere.
If anyone knows how to verify or reset the active SSL certificate for SMTP in the new aaPanel Mail Server module, I would appreciate your help.
@aaPanel_Kern Can you take a look at this?
Thank you in advance.
A. Calhan
