There are any number of reasons why you get this message with the iPhone 5C unlock and some of it will depend on the type of unlock service you used. A tip here is to always use a genuine, trustworthy IMEI unlock service because these are the only ones guaranteed to work without any hassle.
How to Fix No Service after iPhone 5/5/5S UnlockThere are several methods you can use but you will need to go through each one to find on that works for you:
Reset Network SettingsThis is by far the easiest method and one that nearly always works so, if you get the No Service error after you unlock iPhone 5, try this first:
- Insert a SIM card that is not supported by your carrier
- Open Settings
- Tap On General
- Tap Reset
- Tap Reset Network Settings
Toggle Airplane Mode Off and OnAgain, this forces the networks to reset themselves.
- Insert the SIM cards and open Settings
- Tap on Airplane Mode a few times to turn it on and off until it picks up a signal
Power the iPhone 5 Off and On AgainWhen you unlock iPhone 5S and get the No Service error, try removing the SIM card while the iPhone is switched on and then power the iPhone down completely. Re-insert the SIM card and then switch the iPhone back on.
Play Around With Cellular Data SettingsSwitching off your cellular data and then turning it back on again can sometimes work
- Open Settings
- Tap on General
- Tap on Cellular Network to enable or disable it
- Enable or disable 3G and Data Roaming as well
Try Restoring your iPhone through iTunesThis is a last resort method and, before you do it please take a back up of all your data otherwise you will lose it.
- Insert a non-supported SIM card in your iPhone
- Plug your iPhone into your PC and open iTunes
- Click on Backup and then, when that is done, click Restore
- Either restore to factory or restore from your backup, it is entirely up to you.
Have you cut your SIM card down to Size?
If you had an older iPhone and upgraded you may have had a different size SIM card. While you can buy special cutting tools, you can also cut them down yourself provided you are careful not to damage the gold circuit board. If you have inadvertently damaged this and then ordered your iPhone 5S unlock, you will get the No Service error and will have to obtain a new SIM card.
Check your HardwareSometimes the No Service error will appear if the antennae on your iPhone 5 is damaged. Take your iPhone to your nearest Apple Store and have them check it out for you because, as with the cut SIM cards, if the antennae does not work then your iPhone 5/5S/5C unlock will not appear to work either.
We say it that way because, provided you have used a reputable iPhone 5 unlock service, and gene for an IMEI unlock, it will have been successful. You just need to sort out why you have no service and then it will work perfectly.
Source : unlocktheiphone5xpress