Google Analytics not showing on dashboards anymore

It's been a while now (I hoped it would 'go away' on its own) but for some reason the Google Analytics stats on all dashboards (including the Network Admin dashboard) show the circling loading image indefinitely. No stats appear any more.

This has started happening on multiple networks on different VPS's. What they have in common is:
1. running on Nginx
2. WordPress and plugins are up to date
3. using same Gmail account to manage the "Network-wide Tracking Codes" and several site tracking codes.

Is there a known conflict with Nginx? I do not see any related errors in the log files.

Could there be some setting in my Gmail account or in the individual tracking codes that is blocking something? I tried 'Log out from Google account' and authorizing with an access code again. I also tried to set up a Google API project but has the same result...

What am I missing? How to debug? Thanks for any suggestions :slight_smile: