Yeah they silently increased the API limits for CityStrides a few days ago! 
It has been interesting (read: extremely stressful) to figure out how to handle the new load. 
The previous load was manageable with the current servers, but the new load requires something different - that Iām still learning/figuring out.
This is why there has been a little downtime & slow syncing/progress calculations.
Thanks for your patience!