Both iPhone (6s+ and 5s) don't play phone ringtones since iOS10

Hi gang,

I've updated both my 5s and 6s+ to iOS 10.
Since then, neither won't play ringtone when they receive a phone call

They will vibrate though.

I've rebuilt my 5s from scratch as a new iPhone without any restore.

The only thing I've reenabled on it was my iCloud account.

Then again no ringtone with phone calls.

All other sounds are ok: text tone, new voicemail, new mail, sent mail, etc.

I've been thru ALL settings - I almost know them all by heart - I've had an iPhone since the 4.

This has to be linked to iOS 10 somehow, but can't figure out the cause of it 😕

Anyone else ran into that

Thx