It is the official WordPress AMP Plugin available in the official plugin download repo.
https://ww.wp.xz.cn/plugins/amp/
Hello Benjamin. After disabling the AMP plugin the sitemap worked as would be expected. When enabling the plugin again the error changed. You can see it by visiting the given URL again.
Please don’t recommended AMP be disabled as a permanent fix. Realistically disabling AMP can’t be recommended to accommodate your plugin. AMP is not just some random plugin that one could easily do without. How do can this new error be corrected?
