Help Phone Locks when call is started!

[Randoid]

Help! My wife's D3 locks immediately after starting a call. She has to hit the power/sleep button to wake it up to end the call. Anyone know how to stop this? She says she has not changed any settings and my D3 has never done this. Don't see any new apps installed and the phone has been rebooted.

Not a good thing when she has to look at the phone when driving!!!
Please help!
Thanks!!

 

[Randoid]

Help! My wife's D3 locks immediately after starting a call. She has to hit the power/sleep button to wake it up to end the call. Anyone know how to stop this? She says she has not changed any settings and my D3 has never done this. Don't see any new apps installed and the phone has been rebooted.

Not a good thing when she has to look at the phone when driving!!!
Please help!
Thanks!!

I found the cause!! Evidently the screen protector has a little bit of an edge covering part of the proximity sensor and it causes the phone to lock when placing a call!!! (Wish she had told me this happened after putting the screen protector on