problem with mail server mail.domain.com

leon

Dear Support,

I recently received a 3-month Pro subscription (thank you), but I am experiencing an issue with my mail server configuration.

I manage 14 domains, and for each of them I configured mail.domain.com in the domain settings. However, when I check the mail server, only 4 domains correctly show mail.domain.com, while the remaining 10 only display domain.com.

As a result, I am unable to generate separate SSL certificates for those 10 domains. Could you please advise me on how to resolve this so that I can create individual certificates for all domains and ensure they are automatically renewed?

Thank you in advance for your assistance.

Kind regards,
Leon

aaPanel_Kern

Hello, it is recommended that you use the same A record and deploy the SSL certificate, all domain names use the same A record for connection

leon

aaPanel_Kern

I have an MX record and mail.domain.com pointing to my IP. The records are exactly the same for all 14 domains, but only 4 of them show mail.domain.com when I try to create an SSL certificate.

aaPanel_Kern

Hello, it is only used to use one mail.xx.com. All domain names MX records use this A record.

leon

aaPanel_Kern

All 14 of my domains have identical DNS records (A, MX, and the mail.domain.com hostname pointing to my server’s IP). However, only 4 of them resolve correctly as mail.domain.com when configuring an SSL certificate or checking the mail server, while the other 10 only show as domain.com.

I’ve double-checked the DNS records for the 10 domains, and they are identical to the ones that work. The only difference is that these 10 domains were migrated from an old server to the new one, so I suspect the issue might be related to the migration.

At this point I can’t spot any misconfigurations in the DNS itself.

leon

aaPanel_Kern

I’ve made some progress troubleshooting this issue. The 10 domains that don’t provide a separate mail.domain.com are all grouped together in the Dovecot 10-ssl.conf file.
I’m going to configure them separately and see if that resolves the problem.

It looks like this may be related to how Dovecot handles SNI (Server Name Indication). If multiple domains are defined under the same SSL configuration, Dovecot will usually serve only one certificate. By creating separate SSL configurations for each domain (or using proper SNI settings), each mail.domain.com should present its own certificate correctly.

aaP_minerslol44

I’ve had a similar problem when setting up mail servers across multiple domains. In most cases, when some domains resolve to mail.domain.com and others only show domain.com, it typically comes down to DNS or how the mail service handles hostnames.
A slight hint I’d suggest is to double-check that each domain actually has the correct records (such as A or MX) pointing to mail.domain.com. Also, ensure your server is configured to recognize those hostnames individually; otherwise, SSL won’t generate properly.
Not a complete fix, but hopefully that gives you a direction to look into.