[vps-mail] Mail Disappears from certain ISP

[Alvin Tan <alvintan@xxxxxxxxxxxxxxx>]

Hi all,

I have a strange problem with one of my VPS1. All emails coming from a 
local ISP in my country just does not get delivered to the mailboxes on 
this server. Let me elaborate:

1. Watching tail -f ~/var/log/messages, The email is received and status is 
SENT. Destination mailbox is empty.
2. Since I only have SA and some virus recipes, I checked both log files 
(spam.log and worms.log) and nothing is logged. Beside which, both are 
quarantined and would have been in the quarantine mailbox.
3. I checked procmail.log and nothing is being filtered. I made sure that I 
don't have any /dev/null conditions so that the email is not deleted.
4. Sendmail is not configured for BLs.
5. Tested from various same ISP account, and it delivers to all my other 
VPS1 except this one, across ALL email accounts.
6. Finally, checking my ISP mailbox, there are no bounces. This problem 
happens from other  locations too (highlighted from another client)

Any thoughts anyone?

Thanks In Advance,
@lvin