Question Again: Let's Encrypt & Postfix

[skot1708]

Hey Folks,

I think I've read all topics about setting up a correct Mail-Setup with Plesk Onyx and Postfix for our customers - but still got "some" problems.

What I've done so far:
- I've changed the hostname to server.our-domain.de
- I've added the subdomain server.our-domain.de at Plesk and assigned an Let's Encrypt SSL-Certificate
- I assigned the Certificat eat Preferences --> SSL to Secure Plesk AND Mail-Server
- At the Customer Domains I changed the DNS MX Records to server.our-domain.de
- The IP correctly resolves to server.our-domain.de
- Our customers all use server.our-domain.de as imap/smtp adress

But if I check the SSL with a customer Domain here: https://ssl-tools.net/mailservers it says: Hostname Mismatch.
If i run checktls.com with a customer mail-adress everything seems to be fine.

Some customers get Certificate errors sometimes, others not. Have I made any general mistakes?
What's up with the automatic DNS entry like mail.customer1.de - to my understanding I don't need them?

Thank you in advanced & kind regards

Sascha

 

[virtubox]

Hey Folks,

I think I've read all topics about setting up a correct Mail-Setup with Plesk Onyx and Postfix for our customers - but still got "some" problems.

What I've done so far:
- I've changed the hostname to server.our-domain.de
- I've added the subdomain server.our-domain.de at Plesk and assigned an Let's Encrypt SSL-Certificate
- I assigned the Certificat eat Preferences --> SSL to Secure Plesk AND Mail-Server
- At the Customer Domains I changed the DNS MX Records to server.our-domain.de
- The IP correctly resolves to server.our-domain.de
- Our customers all use server.our-domain.de as imap/smtp adress

But if I check the SSL with a customer Domain here: https://ssl-tools.net/mailservers it says: Hostname Mismatch.
If i run checktls.com with a customer mail-adress everything seems to be fine.

Some customers get Certificate errors sometimes, others not. Have I made any general mistakes?
What's up with the automatic DNS entry like mail.customer1.de - to my understanding I don't need them?

Thank you in advanced & kind regards

Sascha

Hello @skot1708 ,
you can check your ssl certificate with CryptCheck , just try usual port like 993,995,465,587.

 

[skot1708]

Thank you for the Link...But I'm not sure how this tool would help me with my question?

 

[garcue]

I had a similar problem, the certificate must cover all third-level domains, ie smtp.domain.tld is required a certificate for the following or in a default wildcard certificate:

• smtp
• mail
• pop
• pop3

I hope I've helped.

 

[garcue]

Also try this tool to verify if the certificate works correctly:

==> // email / test To:​