Why my phone does not have service but has Wi-Fi?

[AC Question]

After I dropped my phone it lost connection to the carrier. The Wi-Fi is working. I put the SIM card on another phone and it works fine.

 

[B. Diddy]

Welcome to Android Central! Which phone? Did you try removing the SIM and then reinserting it? It might have jarred loose from the fall. The other possibility is that you damaged something when you dropped it.