Hello @travis42,
We’re sorry to hear about the experience you had with the plugin.
It’s important to note that there were changes to how Google handle requests to the Indexing API since we released this plugin and now they are being much more rigorous on what is acceptable or not.
We have mentioned this on our documentation since the beginning but recently Google seem to be enforcing the directive where just two types of websites are considerable acceptable, so all others will likely not work anymore: https://rankmath.com/blog/google-indexing-api/
Thank you.