Thank you for your detailed report.
The issue you described was related to a temporary problem within the Geo-Zone backend service that occurred during that time frame. This has already been investigated and resolved in the meantime.
We have already clarified the details directly via email, and the issue has been resolved.
The endpoint loadzones/data.aspx remains supported and no migration to a new endpoint is required.
If you are still experiencing any issues, please feel free to reach out again with specific examples. You can find some details about this instance in the following post: