Can you please provide us with the link to your sitemap so we can check into this further? Sometimes when the sitemap appears blank in the browser, it will still contain the correct source code. When the sitemap is blank but is still outputting the correct code, there is nothing preventing Google from reading the sitemap file.
The server caching the sitemap page can be a possible issue causing the blank sitemap, so that we would recommend if you have a cache plugin or server side cache, please flush the cache. If the issue remains, please disable and re-enable the sitemap feature to force a cache reset. Most cache plugins allow you to exclude the sitemap URLs from being cached and/or minified and we would recommend implementing this for the sitemap to prevent any future caching issues.
We also have additional information in regards to excluding the sitemaps from being included in the server cache at the following link: https://kb.yoast.com/kb/exclude-sitemaps-from-cache/ and also an article outlining the most frequent causes of a sitemap page displaying blank here: https://kb.yoast.com/kb/my-sitemap-is-blank-what-s-wrong/#blank
If you are still experiencing an issue with the sitemap not updating after checking your caching settings, you can also force a cache reset by temporarily disabling the sitemap feature, and then re-enabling. To do so please perform the following steps:
?In WordPress go to SEO>General>Features
?For ‘XML Sitemaps’ Toggle the switch to ‘Disabled.’
??Click ‘Save Changes.’
?Toggle the switch back to ‘Enabled.’
?Click ‘Save Changes.’
?We also have a guide on how to enable/disable XML Sitemaps here: https://kb.yoast.com/kb/enable-xml-sitemaps-in-the-wordpress-seo-plugin/
