For me what worked was logging out multiple times on the watch and logging in again. The time it worked was logging out on the watch, turning off the watch, turning the watch on again and then logging in. Then it got synced.

If you have pending syncs it's worth it to first try the following:

For me what worked was logging out multiple times on the watch and logging in again. The time it worked was logging out on the watch, turning off the watch, turning the watch on again and then logging in. Then it got synced.

Worked for me as well by:

1. Log out of Strava on the watch
2. Turn off watch and wait 30 seconds
3. Turn on watch
4. Open Strava -> prompts to accept terms of service
5. Sync data. No data lost.

Same here.  I had a strong run yesterday and it wasn't sync'ing.  Somebody below mentioned to logout of Strava on the watch and then log back in again.  I just did it and it worked for me.  I'll now uninstall the app on the watch and reinstall.

Try logging out of Strava on the watch and log back in again.  This just worked for me.

You could wait and try your chance tomorrow,  sometime I had 2 day without sync and the day after it synced.

All my synced now so I'll try the install uninstall

I was already on 1.39 so I started a run for 2 minutes, and I didn't sync

I did the "fix method" and now I sync without issues!

Thanks Strava 👌❤️

This isn't good enough. We are paying for this service and there are continuing issues

Worked for me too! 

I've lost my last 3 activities due to this error. I'm on a Galaxy Watch 6 Classic and a Galaxy S23 Ultra. 

I've followed your instructions, and yeah the record did disappear. How nice!

After many different approaches, I found a way to finally sync my ride.

Turn off Bluetooth on phone. 

Uninstall app on phone.

Install app on phone.

Set watch on flight mode

Logg off Strava on phone

Restart watch.

Turn on Bluetooth on both devices.

Log in on watch, and sync works

Foud a way without losing data.

Sign out on your watch

Turn off your watch

Turn off your device

Turn on your device

Turn on your watch

Open strava on your watch

Sync your activitys

My 7 activitys got synced

Tried both, this doesn't work. Please solve! Running a marathon next week and this really sucks!

Same problem here

Fix is to unintall the app on your watch 

I did. That doesn't fix the issue.

same issue Galaxy watch5

No Even though uninstall and install again, cannot fixed

Ça ne marche pas pour moi non plus.

Montre samsung watch 5 et téléphone s24 ultra 

Fixed it by resetting and total new setup the watch, Hope it never happends again.

Three for three on my uploads since the fix.  Thanks for correcting this relatively quickly. (Galaxy 5 pro, Samsung S20)

Same. Any updates for a fix Google Pixel watch 

Thank you for all your posts regarding this. For anyone still having issues, please try resyncing the activity:
Settings button on your watch > 'Tap to Sync' button

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 and direct your email to the attention of Jimi. 

I can confirm the fix worked on my end. Did a 34k bike run and it uploaded flawlessly. Thanks!!