I have a 1.1.2 UK iPhone, which has been jailbroken etc, allowing me to use my existing O2 contract SIM.

Since buying the iPhone a month or so ago, I've happily used it to receive e-mail from both my ISP's POP3 account and also my GMail account and everything worked fine. I noticed this morning, that when I look in my phone's inbox, it says that it was last updated at 8.40 last night, when it should actually check every 15 minutes. Every time I try to collect e-mail with it now, on either account, I get a message along the lines of 'Cannot connect to server.....blah, blah'.

It may be relevant, that the time of 8.40 ties in almost exactly with when I updated / installed a few apps using Installer. From memory, the apps updated were Installer itself (now on 3.0b9), SwirlyMMS and LocateMe. At home, my version of iTunes was recently upgraded to the latest version (7.6?) a few days ago, although has succesfully synced and collected mail since then. I deliberately haven't upgraded the phone to 1.1.3 though!

I've uninstalled both SwirlyMMS and LocateMe, but that hasn't made any difference. I've also carried out a soft reset with no joy. Lastly, I deleted the mail accounts on the iPhone and have set them up again, but that hasn't made a difference.

Any ideas?

Is restoring the phone back to 1.1.2 via iTunes, then jailbreaking etc again an option? Will that even fix my problem?