I'm having trouble using Google's API to update amp pages from a site I'm working on. The site is a Wordpress based site using WP Amp to generate amp pages, it appends /amp to any enabled pages.
I've read the documentation here and it seems like it should be a simple GET request using this structure:
https://cdn.ampproject.org/update-ping/c/s/www.example.com/example-category/example-page/amp
..which gives me a 204 No Content reply (to be expected Google's docs say). However, when retesting via my phone (with cache cleared etc) it is showing the same old amp page not the updated one.
Surely I'm missing something obvious, look forward to finding out what it is.