I have an issue with TLS verification. My domain (domain.tld) website is hosted on another server (cpanel - dont ask) whilst the mail.domain.tld is hosted on my vmin server so separate IP addresses and control panels. An SSL cert was created for the website in cpanel. I’ve copied and pasted that SSL cert and private key in virtualmin using server configuration > SSL certificate > update certificate and key and copied the cert to postfix then restarted the postfix server. Using checktls.com the cert fails with the following error:
Certificate 1 of 1 in chain: Cert VALIDATION ERROR(S): unable to get local issuer certificate; unable to verify the first certificate
This may help: What Is An Intermediate Certificate
So email is encrypted but the recipient domain is not verified
Does anyone have any idea why this isn’t working?