Smart notification is not working

Android or Apple?
Did you read through this thread: https://forums.garmin.com/forum/into-sports/running/forerunner-645-645m/1329743-645m-message-notifications-not-working

I did read it and tried everything still no luck. Phone is xiaomi redmi note 4(android).

Same problem here with Xiaomi Mi Mix 2. Phone and watch are connected, tried every possible setting, but no notifications.

We are investigating an issue where text notifications are not displaying on the watch as expected, but other notifications (phone calls, social media, email) will display. Zidenin and redeneder are you not getting any notifications or just not getting text messages.

I had an issue the other day where Phone Call notifications weren't coming through the watch but all other notifications (email, text, other chat, etc) worked. I restarted watch, toggled the phone slider for notifications to off/on and also add the slider for contacts to on and then restarted the phone. Everything has been working properly since then. I'm on a Google Pixel.

I was not getting any notification on the watch. Yesterday In decided tot install an older version of Garmin Connect (4.1.5) and since then all notifications work. In have not tried to update again, afraid tot lose connection.
?????

Good morning. Woke up this morning and smart notifications for texts and emails aren't working for me anymore. I have an iPhone 6S. Did Garmin push an update to the connect software last night?

Just an update - I called Garmin Support and after checking multiple settings on both my smart phone and my watch and Garmin Connect, they had me "remove my device" entirely from my phone's Bluetooth as well as the Connect mobile app. Then I re-paired my watch to Garmin Connect as if it was a "new" device. Problem solved!

Same problem here with Xiaomi Mi Mix 2. Phone and watch are connected, tried every possible setting, but no notifications.

I have a Xiaomi Mi5. At first I had problems with notification and they did not work at all until I gave some extra permissions to the Garmin app on the MIUI security options. I am sorry because I cannot recall the exact steps to do that, but it was pretty obscure and hidden. Even with that, from time to time watch was unable to reconnect to the phone if I was away from it, but it worked reasonably well.

I finally replaced the official Xiaomi ROM for a Lineage 15 (based on Android 8), and since then smart notifications have worked like a charm out of the box. Unfortunately I cannot recommend you to do that unless you have a strong technical background because that will void the phone warranty and there is a risk to brick the phone (and the process has a lot of steps and it is quite confusing... even for a computer scientist like me).

Bottomline: Some vendor "improvements" to the vanilla Android implementation do more harm than good.