Emails not working after upgrade: certificate verify failed

[JammyDodger]

There’s some discussion and advice about a similar error in this recent topic that may be helpful

Email Hostname Certificate Mismatch Causing sidekiq Queue Overload, Severe Site Instability

When I connect to that host and test the STARTTLS I get a certificate that does not match the hostname: Certificate chain 0 s:/C=US/ST=California/L=Sunnyvale/O=Proofpoint, Inc./OU=ESP/CN=*.pphosted.com i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=Thawte RSA CA 2018 1 s:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=Thawte RSA CA 2018 i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Global Root CA and it did not expire yet: notBefore=Jun 12 00:00:00 2020 GMT notAfter=Sep 14 12:00:…