I went to the plugin in WordPress that produced my sitemap ‘Google XML Sitemaps’ and clicked on the settings link (see the image below).
Under the section ‘Basic Options’ I found that there was an option to ‘Include sitemap in HTML format’.
I unchecked this box (this was generating a copy of my sitemap, in the HTML format).
Next, I went to the top of the Google XML Sitemaps settings under the heading ‘Result of the last ping’ and resubmitted my sitemap and sub-sitemaps (see the image below). This also notified the search engines that they had been updated.
Now go back to Google Search Console and Validate the Fix.
Google Search Console will now check that it has been fixed…
It might take a few days, to several weeks for Google’s Search Console to check and validate the error, but the ‘Submitted URL Marked ‘noindex’ error should eventually disappear.
And if you’re lucky… You’ll also get an email from the Google Search Console team.
There are several links on the Yoast Help page that could take you to potential solutions. Check that your sitemap conforms to the requirements and Yoast and Google Search Console. I.e. the Yoast sitemap ends in sitemap_index.xml, instead of sitemap.xml…