Messenger notifications not showing on iPhone/Watch

Which messenger app do you use?

Did you already try to force restart your iPhone and Apple Watch?

Force restart iPhone - Apple Support

To force restart your watch, press and hold the Digital Crown and the Side button together for about 10sec, until the Apple logo comes back again.

Also have a look at the related article, to be sure, that all settings are enabled accordingly:

Notifications on your Apple Watch - Apple Support

I just had my Watch returned after battery renewal. Paired it as a New Watch (no backup).

Everything worked!

I only had to add back a suitable face, add back alarms, changed a few settings.

Even Whatsapp app appeared.

Always a good "start afresh" option.

FinsFan_1972 wrote:

Facebook Messenger.

Whereas Meta have now introduced a Whatsapp app for Watch, they have yet to do so for Facebook.

Therefore it is pot luck if Facebook notifications are guaranteed to work, but it is Meta's responsibility to make them work.

Good news 🙂