Have you spoken to you phone network provider about settings for this. Unknown numbers maybe blocked by them by default. Double check your settings. When you go into the phone app Tap on the 3 dots on the top right Go into the app settings. Is the call ID and spam protection turned off Also go into block numbers Is the block unknown or private numbers off
It isn't on the network providers end! I have 2 sims in my phone and neither accept unknown numbers! Call I'd and spam protection is on...should it be off? It doesn't seem to matter whether it's on or off to be honest and it isn't set to block numbers!