Hello ming63.
Thank you for using Apple Support Communities. We'd like to help get your iMessage notifications properly working again on your Apple Watch. To confirm, is this the only notification that isn't being received on your Apple Watch? We'd like to check some settings and make some recommended troubleshooting steps. These steps should help you out out. First, review this resource here: Notifications on your Apple Watch - Apple Support
When your Apple Watch locks or you turn on Do Not Disturb, your notifications go to your iPhone:
When your Apple Watch is locked, the lock icon
appears on the watch face.
When Do Not Disturb is on, the Do Not Disturb icon
appears on the watch face. To turn this feature off, swipe up on the watch face, then tap the Do Not Disturb button
.
If your settings are properly set up, we recommend that you unpair your Apple Watch from your iPhone and set it up again. This step usually helps refresh things. Just in case, the resources below can guide you through this task: Unpair and erase your Apple Watch - Apple Support & Set up your Apple Watch - Apple Support
We hope these steps help you out. Thank you for using Apple Support Communities. Best of luck.