iPhone 6s not displaying names on text messages

I tried the answer above but that didn't work for me. After some trial and error turning off contacts in iCloud and then turning them back on worked for me.

1. Go to settings > iCloud
2. Turn off "Contacts" option
3. It will ask you if you want to delete the contacts synced on the phone or keep them. I deleted them.
4. Verify that the contacts are gone. (Optional)
5. Go back to the iCloud settings and turn the contacts on.

This worked for me. Took about a minute for all contacts to resolve in Messages app. I am on iOS 10.2 and this happened when my phone turned off unexpectedly due to battery issues.

None of the answers here worked for me. I had to:

1. Open the Settings app.
2. Scroll down to Contacts.
3. Tap the Short Name option.
4. Turn off the Short Name switch at the top.
5. Go to the home screen.
6. Open the Settings app.
7. Turn the Short Name option back on.

After that procedure, the Messages app on my iOS device once again showed names instead of phone numbers.

1. Go to Settings->Messages

2. Scroll down to the header SMS/MMS

3. Uncheck "MMS Messaging"

4. Restart iPhone

5. Go back to "MMS Messaging" and turn it on

This should fix the problem

Edit: This bug has been reported to Apple by many users under bug ID 22817380