Force e-mail to download from server

[uzair]

Hi there.

I have a user who's e-mail is setup on sugarcrm, but something odd happened the other day. He logged out at the end of the day & happened to get an e-mail that evening. The next time he checked his e-mail was the next day. You can see the e-mail sitting on the e-mail host's server, however for some reason, SugarCRM refuses to download it. I can download everything else, but just those two e-mails refuse to be downloaded.
I have a feeling it has something to do with me not having setup a cron entry for cron.php file, but can't figure out why it won't download it when we manually check the mail. Mind you we tried on GoldMine (our old CRM) and it downloaded it fine.
I also tried recreating the problem, but to no avail.

Anyone have any suggestions? Does anyone know how Sugar determines whether a message needs to be downloaded or not (ie: how does it differentiate between old e-mail messages it has already downloaded and new ones?)

System Info:
E-mail hosted on GoDaddy servers, setup for pop3.
OS: Ubuntu 8.04 (Hardy)
Sugar Version: 5.2.0f (Build 5688) (community edition)
Webserver: Apache/2.2.8 (Ubuntu)
PHP: 5.2.4-2ubuntu5.6 with Suhosin-Patch mod_perl/2.0.3 Perl/v5.8.8
MySQL: 5.0.51a-3ubuntu5.4
(if you need anymore info, please ask)