Phone black when making a call

[Brasmall]

My Samsung S9 goes black/blank once i press call whether its whatsapp call or normall call.on the back ground it dials the number u can here the phone ringing on the other side..you then need to press a lock button for the screen to show otherwise it will stay black till the conversation is over..please help on how to fix this 

[donovangregg2936]

That normally means you have to update your whatsapp

[goglish]

Mine as well does the same blackout
while I'm busy with any activity not only wattsap what can be the problem