As others are noting, I'm having problems with Activities in Garmin Connect. I'm getting 400 errors.
I'm including some steps and screenshots to reproduce. I'm using Chrome and Internet Explorer.
Steps to Reproduce:
1. Login to GC via Chrome or IE.
2. Click on the "3 line" menu button.
3. Click on "Activities"
Result:
I get two (2) back to back generic 400 pop-up errors. (See attached screenshots)
Once I dismiss the pop-up windows, the activities load.
5. Then open an individual activity, and the activity fails to load all data. (All the pace, HR charts, and run detail.)
6. Then, if you change the category (e.g. Change from "Running' to "Train Running") all data returns.
Hopefully this helps.