Notification to mobile stopped working

I’m running my HA instance on Docker (installed on an Intel machine with a Raspberry Pi Desktop for PC operation system).
Somehow the notification to mobile stopped working.
From the server side (via Automation or via the Developer Tools, run a service) it looks OK, but the notifications do not reach their destination mobile
This is undoubtedly a server issue (not frontend/mobile, tried it with multiple mobiles, Android and iOS). I uploaded the exact setup configuration to another machine with HA and with that machine the notification works OK.
Any clue of how to solve this?

Are there any relevant errors in Settings → logs?

I couldn’t find any errors in the logbook.
It shows like the service is running OK:

Same via automation, run OK, but not messages arrive to mobile.
No errors in the log (setting log)

Check your notifier entities in developer tools → states. Maybe _2 got appended to the entity id.