It fixed now

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.

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.

Yes Moreover, the system page says it is working.

It's still exists for me

Same error appears again for US locations.

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.

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

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

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.

Yes it's same to me and makes me crazy

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