I have same issue but I can only subscribe 2M calls. I got unsuccessful message trying to over 2M calls.

Yes it's same to me and makes me crazy

The issue is repeating today! As I observed the issue it mostly success with responding requesting again with same request parameters after 15 seconds later after getting error.

Why Weatherkit developers still don't care the issue. There is no problem according to: https://www.apple.com/support/systemstatus/

Yes it's fixed for now. I hope it won't down again.

Yes I agree with you, my app doesn't work sometimes because of the error. Users complaining to me and I can't say to my users Apple developers work on the issue. They think this my fault. My app lost 10.000 users because of Weatherkit unavailable. This is the first time that I use an Apple service and will be last.

Same error appears again for US locations.

It's still exists for me

Yes Moreover, the system page says it is working.

As I observed the issue is not stable sometimes works sometimes doesn't work. I added a web service which has stable connection server with weatherkit for a solution.

I contacted with apple developer support team I sent all headers data with unsuccessfull request and other details also I created a video that shows making api request with postman with all details. I can't understand why they still asking questions.

It fixed now