"Caller not receiving calls at this time" message

You would need to ask the person whose number is giving you that message. If someone blocks your phone number on an iPhone, you don't get any indication at all. Your call just goes to voicemail. Is this a message you hear through the earpiece? Perhaps it's something through their carrier.

Definitely sounds like a carrier thing to me. I suppose it's possible that Android phones have some type of built in feature that allows that but it's been about 10 years since I've had an Android so I'm a bit behind on those features.