I am running cpanel, I have a customer who has his email forwarded from his domain name on my server to his Yahoo account, the problem is while all of the email gets forwarded, only some of the originals stay on the server for him to download later. We removed the forwarding and he only received some of the emails sent. We tested this from several accounts including an account on the same server and that email did not get delivered.
I checked the logs and could not find anything out of the ordinary. Any input is appreicated.