The email notifications are not working after upgrading from v11 to v12 (v12.1), including sending the test email.
There are warnings on the backup jobs: " Sending e-mail report Details: The remote certificate is invalid according to the validation procedure. "
Every time you send an email report, Veeam Backup and Replication v12.1 validates the certificate received from your email server during email report configuration, indicating that the certificate has likely been modified.
It's easy to fix this issue, you need to open the global email notification settings and save the configuration again, accept the verify certificate prompted and save the settings.