I have the exact same problem as described in the first post, and I didn't see a resolution posted in this thread. My Palm Pre 2 syncs to my Exchange email at work via an https address. It worked fine for about the first 3 weeks I had it, then stopped working with the WiFi enabled - synchs right away when I turn off the WiFi. Other items of interest:
- I have a computer on the WiFi network with Outlook set up to sync to my Exchange email in exactly the same way without a problem, so it doesn't appear that the provider (Verizon FIOS) is blocking anything
- I also have 2 Yahoo email accounts and 1 Verizon email account on the phone, no problems with those on WiFi.
- All other network activity I try on the phone (browsing, apps, etc.) work fine on WiFi
- I took my phone to the local coffee shop, and my Exchange email works fine on their WiFi
I am out of ideas. Anyone else?