When I try to pair the heart rate with my iWatch, it never connects and it also flickers on my iWatch. The app closes an opens for a few seconds and then just disappears.
This used to work and it seems to coincide with me trying to pair with an Apple TV. However, i’ve tried it at work which is quite far from my Apple TV and same problem.
Hi, I had the same problems with my Apple watch. I reinstalled the Zwift Companion App and now it works fine for me.
thanks for the suggestion @Marc_Grywatz, I appreciate it.
I tried uninstalling both application (Zwift and Zwift companion) on my phone and also removed it from my apple tv. Restarted my phone and watch before reinstalling them but I still have the issue. 
Same issue here. Worked the first time about a week ago, and hasn’t worked since.
It seems that there are some problems with the apple watch.
Is your watch shown in the pairing screen? In my case it was shown, but with “no signal”. So I tried to reinstall the app, and it worked.
Do you have the latest OS installed on your phone and your watch? Maybe this can help?
And how are your settings for zwift in your phone? Is zwift allowed to read your heart rate?
I had the EXACT same issue with both the Zwift app and the Zwift Companion app. They have recently pushed an update to the companion app that fixed this. I hope they bring the same fix to the Zwift app.
To reiterate, the issue is when pairing the apple watch to an ios device. After it pairs, the apple watch will display the zwift data, but flicker between paired/unpaired. It is unusable. I can though, because of the recent fix, use the zwift app on my iPad and then use the zwift companion on my iPhone (with my Apple watch paired to my iphone) to get a heart rate tracking on Zwift. Prior to their recent update to the Zwift Companion app, this also resulted in the flickering paired/unpaired issue.
It would be nice to see the same fix come to main Zwift app, so I can return to zwifting with just one device. I would like to be able to just put my iPhone on the treadmill while running. Two devices is a bit much.
I can see it in the pairing screen and when I pair it, it looks like it’s working and paired. However, on my watch, the app will pop up for a few seconds, disappear and then flick back and forth for another few seconds. By flick I mean it pops up and shuts down over and over.
Yes, I have the latest OS installed.
Yes, everything in Apple health is allowed for the Apple watch for the Zwift app. This worked a week or so ago and stopped working out of the blue. I thought it might have been when I added an Apple TV in the mix but I have uninstalled the app on my apple TV, Phone and Watch. Then reinstalled only on my Phone / Watch and still have the problem.
I have contacted Zwift support earlier today and sent them a video of the behaviour since it looks like other people are encountering this issue and it’s very annoying. Especially if you have strict goals such as training for a Triathlon or something similar. I will use the Indoor Cycle workout on the watch to track for now. Hopefully this gets resolved quickly.
It started working again out of the blue… so I am not sure what the solution is but it’s working now.
I had both Zwift and the Companion all installed on the watch. Uninstalled Zwift and just have the Companion. Now seems to work.