Sitemap is HTML

In regards to your issue, the error you receive on your sitemap can be caused by a number of issues, including the submitted URL or that the sitemap page is being redirected. We also have additional information on the error that your sitemap is not in the correct format and is an HTML file at the following link: https://kb.yoast.com/kb/why-is-google-saying-my-xml-video-sitemap-is-an-html-file/#redirect
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Can you please try the aforementioned recommendation and let us know whether this resolves your issue?

No further response, setting to resolved.