iPhone Messenger incoming Call no notification!!

I checked all over the Internet and did all the possible checks and sound & notification settings yet no incoming call notifications or alert or sound for any Messenger calls made from known Contacts. Even though when I kept the Messenger app open when I expect calls. But see a missed call notification immediately after my friend called me!

Anything from Apple support or anyone from the community why I can’t hear a ring tone or incoming call alert from Messenger or Viber calls? Appreciate it!

I'm using the iPhone X with latest F/W update.