Restoring HTC EVO 4G to stock
Root access is unlikely the problem, but you can go back to stock and see what happens. Best and surest way back to stock is flashing a .sbf. The .sbf is the stock image provided by the retailer. If you're on Windows, you'll need RSD Lite to flash I believe. If on Linux or OS X use sbf_flash. You'll also need the .sbf for your particular device, but I'm not sure where the Evo images are; Google can probably help.

But again, I'd blame the network before an issue from root.