Hi,
Same issue with my S20 Ultra. I rang Samsung, went through all of the tech support options, they said they need to repair the device. I'm assuming its a bug with Android on the latest S20s that is causing the issue because it's not my network, I put my sim card into my old Samsung Galaxy S9+ and rang my number off another phone withheld, and it accepted it as long as the auto reject of private numbers setting is off. However I cannot accept private incoming calls to my S20 Ultra even with the setting turned off that auto rejects private numbers.
If you ring tech support they'll tell you to soft reset the device, try entering some call barring codes/passwords, and reset the APN to default, as well as boot your device in safe mode and attempt to receive private calls that way too. None of them worked.
It's definitely something wrong with either the latest Android software or the S20 range. Ring Samsung for a repair.
