Exim error message
SSL verify error: certificate name mismatch: "/OU=Domain Control Validated/OU=EssentialSSL Wildcard/CN=*.mailchannels.net
Does this mean that mails are not delivered?
No, this error has no impact on email delivery. Basically, the verification status is logged but this does not have any impact.
Why do I see this error?
Some changes were rolled out in Exim 4.86
JH/04 Certificate name checking on server certificates, when exim is a client, is now done by default. The transport option tls_verify_cert_hostnames can be used to disable this per-host. The build option EXPERIMENTAL_CERTNAMES is withdrawn.
JH/06 Verification of the server certificate for a TLS connection is now tried (but not required) by default. The verification status is now logged by default, for both outbound TLS and client-certificate supplying inbound TLS connections
As a result of these changes, the certification verification status is logged in exim logs. If you do not want to see the error, please disable tls_verify_cert_hostnames in exim.