On taping for outgoing call, my Pixel 2 fhone screen becomes blank/dark.

[Android Central Question]

The phone system remain working, call gets connected & thereafter screen wake up .

 

[Rukbat]

The proximity sensor is supposed to take effect in phone calls, keeping you from "cheek dialing" during a call. That can get wonky if you have a case that activates it. (Placing my metallic pen near it activates it.) So make sure it's still doing the same thing with no case. If it is, the phone's still under warranty, and a bad sensor is covered. If it works okay without the case, complain to the case manufacturer. Anything metallic at about the right half of the top or the phone will trigger it, so if they put something metallic up there, they're going to have to do a redesign. (Not everyone who's called a designer is actually competent.)