Incoming calls not received

[IainMac]

When a call is made to my iPhone, it does not ring out. The caller is routed straight to voicemail.  If the caller rings again immediately, this time my phone rings. This happens to all incoming calls.

[pgn]

Check your Do Not Disturb settings on the handset, @IainMac 

Android/Pixel phones can do this if left face down - 1st call rings silent, second call in a 30sec window rings audibly, if set that way.

Starred Contacts will always ring, as a tip. iPhone may have a similar function. Good luck, @IainMac.