There has been so much interest recently in my post on the No Service error message that appears to be plaguing particularly 3G iPhones, that it seemed appropriate to put up a more detailed summary of possible fixes for the "No Service" message on the iPhone.
Below is a summary of all the suggestions from the many comments on the original post (thanks to all the commenters!) and from several sites around the web.
- First, try a complete reboot of the iPhone. Hold down the Sleep/wake button at the top right of the phone and the round Home button below the screen on the front of the phone at the same time, until the screen goes black and an Apple logo appears. At this point you can release the buttons and wait for it to finish rebooting.
- Try switching Airplane mode on and off.
- Disable 3G. Sometimes the iPhone is not fast enough in switching between 3G and 2G. [LINK]
- Dock the phone or attach a USB cable (attached to nothing on the other side)
- Charge the phone fully, using the wall adapter.
- Reset Network Settings.
- Important: The following fix will lose any wifi settings and passwords you have set up. You may want to note them before going forward.
- Go to Settings: General: Reset
- Click Reset Network Settings
- Enter your passcode if you have created one
- Click the red button: Reset Network Settings
- The iPhone will take a minute to shut down then it will reboot.
- Re-seat your SIM card.
- Insert the end of a paperclip into the hole on the SIM tray (look for a tiny hole in the long, narrow rectangular metal shield in the center of the top edge of your iphone. NOT the headphone jack - it is a much smaller hole.)
- Press it in until the SIM tray pops out. This is sort of the way we used to eject jammed CD trays - push a paper clip into the eject hole.
- Remove and replace the SIM back into the tray.
- Push the tray back in.
- Attach a small piece of Scotch tape to the outer side of the SIM card (the side withoug contacts). This put just enough pressure on the contacts to increase signal strength for some people. LINK
- Restore your iPhone using the latest version of iTunes.
Other possible fixes (untested, try these at your own risk!):
. NOTE: I have no idea if any of these signal booster devices work - buyer beware.