Emails not deleted from external account server after collection

[SynUK]

Hi,

I have setup a couple of external pop3 accounts under a user, and the emails are collected and put into the ZCS mailbox as they should be.

In the settings for the external account, I have also ticked the "Delete messages on the server after downloading them" option but all the emails that have been downloaded still stay on the remote external account server.

This means that I now have about 800 emails on the external account server that are also on my ZCS server. Eventually this will start causing a problem on the external account server as I presume they will just continue to build up.

Shouldn't ZCS delete them from them from the external accounts server once it has collected them as I have the "Delete messages on the server after downloading them" option ticked ?

Thanks.