Short summary: I got an HTC Inspire 4G a week ago. It was giving me Wifi problems even when connected with a strong signal, as detailed below. I exchanged it for a new HTC Inspire. Now the replacement phone is doing the same thing. With my last phone, I found that for several hours of the day, when it said it was connected to my home Wifi with a strong signal, it would stop syncing or pushing anything data related - gmail, exchange mail, weather, etc. I would get an exchange sync error in the status bar. If I told it to update weather when it was not working, the weather widget would say there is a connection error. It would stay this way until I restarted the phone or turned Wifi off and then on again - then it was fine for several more hours. If I turned Wifi off altogether, my data through AT&T network would work, so it seemed to be a problem with Wifi specifically. This would occur standing right next to my modem and when my computer was not having any problem with internet. I also tried restarting my router - no dice. I contacted HTC and AT&T. I did a factory reset which didn't help. They told me to exchange my phone through Amazon for a new one. For the last 3 days I had both phones before I returned my old one. My new phone has been fine for the 3 days and did not give me any sync errors even when the old phone was giving me errors at the exact same moment. But now I am getting the same error on my new phone! It's acting the exact same way - syncing stops working, same exchange server error message, and the the problem fixes itself if I turn Wifi off and then back on or if I restart my phone. What could the problem be?