I have 7250 activated thru BES running 4.0.3.11 (Domino).
Receiving emails ok but after awhile emails disppear...What the ?
No other devices having issues. Checked the following settings..

Keep Messages: 15 days
Email reconciliation
Delete On: Handheld
Wreielss Reconcile: On
On Conflicts: Mailbox Wins.

Any idea why this is happening...

Thanx !

How much free space do you have? Go to Options > Status to check. Try deleting the phone call log and clear the Browser cache to free up additional space.

this is most likely the problem... some times resetting the BB wil help it clear some space as well. especially if you are running the 4.1 version of the device software ( not sure if the version you posted is that of the device or the Bes)