it will be most likely not a workaround but the neccessary configuration for this case. as mailcow is hosting multiple domains. xmpp.example.com is our mailcow.
example.com is the domain that should be served. but the xmpp server on mailcow needs to know that it is responsible for example.com (he maybe knows but he’s responsible for im.example.com - but currently i cannot tell you are (also) responsible for example.com.
and in the text you quoted: Note about certificates: When requesting/generating certificates for your domain, you need your certificates to be valid for the virtual host name, not the domain that your SRV records point to. For more information see ‘Which domain?’ in our certificate documentation. So that’s what Note about certificates: When requesting/generating certificates for your domain, you need your certificates to be valid for the virtual host name, not the domain that your SRV records point to. For more information see ‘Which domain?’ in our certificate diekuh said already - that the certificates must be right for “example.com” in this case. So it’s not just redirecting to a different server, the different server needs the right certificates also.