mail notifications on Apple Watch 4 aren't working

I'm having a similar issue (and there are other similar threads in the Apple Community Forums). Seems to have started happening around the time of the Watch OS update.

Today I spoke with a Senior Support specialist at Apple, who has escalated this to their engineers as a bug.

There's a workaround that you can try. It worked for me but your mileage may vary:

1. On the WATCH got to Settings > General > Wake Screen

2. Toggle the top 3 settings (wrist raise, crown up, audio apps) to the OFF position

3. Send yourself a test e-mail

If you still don't see it go to the Watch app ON YOUR PHONE

Go to Notifications > Mail

Choose "Custom" > Allow Notifications

Turn ON notifications for all accounts you are interested in and allow all sounds and haptics, then try it again.

The combination of these 2 things got it going for me and the Apple person says it should be fixed in the next update.

Hope this helps.

Seems to be an issue if you have your mail notifications set to Custom. If you have more than one mail account on the phone, but only wish to have notifications for less on the watch, they will not work. Once I turned my watch notification to Mirror my iPhone, the notification will work. Also, check on the iPhone for your vibration settings. For some reason, with the latest update, vibrations are set to Default, which is no vibration. Apple is aware and we should see something with the next update.