Lost over 3000 AMP pages in Google Index

Can you please re-crawl your website in Google search console. And check once whether having the same issue or not. Then do let us know.
For reference please follow this tutorial: https://ampforwp.com/tutorials/article/how-to-send-for-recrawling-your-website-in-google-search-console/

There are no errors to fix.
The pages are just not indexed any more.
They were indexed before October 15. Then suddenly, not indexed.
Also, Google has disallowed indexing requests.

Can you please share URL link at which you are encountering the issue, We will analyze it and let you know back.

https://www.aier.org/amp

Can you please provide us the export of AMP option panel, we will import it once and let you know.

For reference please follow this tutorial: https://ampforwp.com/tutorials/article/how-to-import-and-export-the-amp-option-panel-settings/

JSON Export file

We imported your AMP configuration but were unable to recreate the issue at our end. Can you please share the list of active plugins on your site. We will go through them and let you know.