Hello,
I need to secure the mail, hosted on a different server. The DNS zone are correctly set and all the records related to the mail point to the mail server.
I tried to install a certificate (in plesk) by flagging only the mail but it does not work.
There is something I do not know? Can the mail server get the certificate from LetsEncrypt?
Best regards
Are you requesting the cert from that other server?
as you set mx recode with some domain name, MTA will need to provide certificate for that domain name.
making sent emails not trashed by other side is just different can of worm (spf, dkim, dmark, ip reputationm etc...) you will better get a smtp relay.
and actually signing/encrypting is yet another thing, (s/mime) while its uses certificate LE sodent sign for you
Hello,
yes, in the first server the mail and webmail are not secured, in the second server I cannot secure the mail and the webmail.
DNS and zones are OK
What is the IP and FQDN of the server that needs a certificate?
the website zweikapitaene.de is secured on 167.86.103.136 and is ok.
The mail should be secured on 217.160.144.252
MX Records
Your MX records that were reported by your nameservers are:
10 mail.zweikapitaene.de 217.160.144.252
You keep adding information that isn't requested and irrelevant.
Does 217.160.144.252 run Plesk?
What exactly do you mean by:
Is that webmail?
OR
SMTP?
OR
Both?
OR
Other services too?
217.160.144.252 runs Plesk and at least the SMTP should be secured
Why is Plesk failing to obtain a cert?
I repeated just now the procedure in order to post the error message and Plesk was able to secure mail and webmail
Glad to hear that 
It is not a complicated procedure... flag two boxes and click enter...
And yet it failed once before - LOL