No automatic POP3 polling for 1 account

[Koraahr]

Hi everyone,

I have some strange behaviour with our Zimbra server. Every user has automatic polling of at least one external account enabled and working, just my own account doesn't anymore.
Everything is set right, COS, account, datasource (checked with zmprov gc|ga|gds), as some days ago it still worked.
All I notice is that in /opt/zimbra/logs/mailbox.log there is no entry like '[ScheduledTask#] [name=...' etc. for my account, all other accounts resp. data sources have one.

Any ideas where I could look or what I could try?

Thanks in advance