Email server (Cpanel/dovecot) delivery analysis and fix

There seems to be 2 clear errors occurring with our emails that we need to resolve: 1) Some of external emails are not getting through to inbox (or the outgoing emails may not reach the recipients). 2) Our system shows that our emails going out of the CRM /mail system may not be reaching people and getting read. Only a very small amount of emails state that they have been “opened” as their status, which is telling us that customers aren’t receiving the emails. We think these two errors may be related, or possibly related to mail queue size, however, more investigation into this is required.