Pop3(Secure)Socket and MessageCount

I need to poll a mail server for a project I am working on.
Usually, I keep the Pop3SecureSocket open all the time (and reopen it in case the connection was lost in between).
While this works ok on the first run, I noticed MessageCount will not increase even if new mails arrived since the last poll.
Do I have to reinitialize the socket before I start another poll or is there some other trick besides restarting the app?

It could be that the pop3 server doesn’t support persistent connections.

I see. Thanks, Greg!