@JK9d3r,

The problem may be that if for some time the N900 doesn't use the connection actively, the provider might be closing it.

I had a similar issue (Germany, blau.de provider using E-Plus network), where sometimes I would stop receiving mail. I had the polling interval set at 1h. I changed it to 30min and I've never had the problem again.

A possible solution might be to have a script pinging something every 10min or so, but I haven't bother to write one (since it now WORKSFORME