I am having trouble accessing all athlete activities (my own) from the url in Strava\'s api documentation.
I am able to get my own year-to-date stats:
ht
I don't have enough points to comment, but I have done exactly this recently!
In order to make it work you have to set scope=activity:read (instead of 'scope=read') in Step 1.
scope=activity:read
scope=read