What do you mean?
The screen is meant to go black after a period of not use to save battery.
Tips to fix-
Remove any accessories.
Third-party protective films, cases, stickers, or glass screen protectors may block the sensor and should be removed. It is recommended to use Samsung-approved accessories only.
Restart the phone.
Once you’re off the call, restart the phone by swiping down from the top of the phone with two fingers to open Quick settings. Tap the Power icon. Tap Restart, and then tap Restart again.
Check Double tap to turn on screen motion gesture setting.
If the screen doesn’t turn on during or after calls, turn off Double tap to turn on screen feature.
Open Settings and then tap Advanced features.
Tap Motions and gestures.
Tap the switch next to Double tap to turn on screen to turn it off.
Clean the sensor with a soft cloth.
The proximity sensor is located at the top of the phone, although the exact position will vary by model.
Clean the front of the device with a clean, soft cloth.
Check for a software update.
Samsung frequently releases software updates that will improve the performance and function of your phone.
Navigate to and open Settings, and then swipe to and tap System Updates or Software update depending on your phone.
Tap Check for system updates or Download and install to check for available updates.
Yes, Samsung has no fix. That's hard to believe but true!
I use my phone for work, using earbuds and am not holding the phone. I will make the call and in 2-3 seconds the screen goes dark and I can tap the hell out of the screen to get it to come back up. Not great when needing to push the keypad for options or extensions, or for wanting to hang up.
So, there is no fix from Samsung? What now?