Last session I added was last night and it went across fine.

It does occasionally hiccup and run slow although cant remember it happening recently. Might be worth checking its still connected.

Worked fine for me about 2 hours ago. I have experienced the odd delay. Try again a bit later.

It's connected fine, just disconnected and reconnected connect still not working, last sync was 6 Feb.  Sync via zwift has been fine.

It happens to me once in a while. The easiest solution is to  'disconnect' from Strava & then reconnect again. Pretty painless and cures it every time for me.

mine seems to work ok for ages and then it goes wrong and nothing syncs . pita .

seems to happen when the devices have a few weeks of activities , need to remember to clear them more often .

if you have it on Garmin Connect , download the gpx files and upload them manually in strava .

My Garmin express did an update the other day, and it didn't sync until I had clicked to give it permission to do something. (Garmin 800 plugged in via USB)

Well reconnect and test activity has synced okay, but the previous 5 rides aren't there. What a faff

Had this problem once reloaded the app then worked fine

Mine does this when the device needs a software update