Remcam and Remvid not working if phone is on lock screen

[Graham]

It seems that remcam and remvid do not work if the phone is on the sleep screen (Samsung S10+ not rooted). They only seem to work if the user is on the phone.

Does anyone else get this happening, or is there a fix?

[HAMED]

I've had the same problem since three weeks. I don't know how to resolve this. 
Previously I didn't have this problem.