I can confirm that since implementing the fix above, I've gone for two runs and everything is sync'ing fine now.  Samsung Smart Watch 4 and Sony Xperia 1ii.

Hi Scout, your procedure didn't fix the issue on my Ticwatch Pro 3 Ultra GPS.  I have version 1.39 installed.

Hey @ElectricGrazerr, 
If you have issues after doing the above, please submit a support ticket. If you have trouble with our online form, you can send an email to support@strava.zendesk.com. Please direct your email to the attention of Jimi. 

I have the same problem and lost 6 hours of training data. Not happy about it.
I tried to delete the Strava app and reinstalling, same on my phone, disconnect/reconnect, checked all the settings,... nothing fixes it. 

My watch has a slightly different message: Parameter specified as non-null is null: method yb.e.apply, parameter apiErrors 

It is also impossible to show directly my activity on my phone. It opens Strava, but not the activity itself. 

Trying to manually sync (tap to sync button) does not work either after trying like 15 times over 3 days.

I am experiencing this issue on the following watches ...

- Fossil Juliana HR Gen5 (Strava 2017 era app)

- Fossil Gen 6 (Strava v1.39)

Some workouts will sync after waiting a long time and rebooting/playing with it in various ways, it seems to help to connect to wifi and disconnect from bluetooth and things like that, I can't make heads or tails of it. I have lost some workout data to this issue 😞

Hello all,

I am still facing this issue on Fossil Gen 6 with Strava app v1.39. I have tried the proposed solution above (uninstalling and also full watch factory reset) but no success.

Potential workaround

However, one thing I noticed is that if I change the battery mode of the watch to "Time only" then put the watch on the charger, the watch will return to the normal mode and all pending activities get synced. I need to repeat this whenever I want to sync a new activity. Not optimal but a good temporary solution.

Best regards

@roda, @Gauthier, @guideX & any others that are still having issues; please submit a support ticket  and direct your email to the attention of Jimi. 

If you have trouble with our online form, you can send an email to support@strava.zendesk.com. 

Same problem on Ticwatch Pro 3 Ultra... I tried all of possible solutions above 😕😕

I reinstalled the app on both the watch and the smartphone.

Can I view my stats anywhere or is my only option to delete my run first time using strava not too impressed now that my data is lost

Hi All, 
Thank you for all your posts. We will be closing this post for comments. If you are still experiencing this issue, please submit a support ticket and direct your email to the attention of Jimi. Please be sure to include the device you are using as well as the version so our team can further investigate.