The error 'sitemap could not be read' in a WordPress context often occurs due to one of the following reasons:
Incorrect Sitemap Format: The sitemap may not be in the correct XML format that search engines can understand. This could be due to an error in the plugin creating the sitemap or invalid characters interfering with the XML syntax.
URL Errors: The sitemap might contain URLs that are broken, leading to 404 errors. Search engines trying to crawl these links will thus report that the sitemap could not be read.
Site Visibility Settings: In WordPress, there is a setting under 'Reading Settings' called 'Discourage search engines from indexing this site'. If this is checked, it may prevent your sitemap from being read.
Sitemap Location Issues: The sitemap might not be located in the place where search engines expect to find it (usually the root directory).
If you come across the 'sitemap could not be read' error, here are the steps you can take to resolve it:
Check Sitemap Format: Ensure your sitemap is in the proper XML format. Use an online XML checker to validate the syntax. If you're using a plugin to generate your sitemap, ensure it's reputable and up-to-date.
Fix URL Errors: Check the URLs in your sitemap for any that return a 404 error. You can use tools like Google's URL Inspection tool in Search Console. Replace any broken links with the correct URLs.
Review Site Visibility Setting: In your WordPress settings, go to 'Reading Settings' and ensure 'Discourage search engines from indexing this site' is unchecked.
Check Sitemap Location: Make sure your sitemap file (usually named 'sitemap.xml') is located in the root directory of your site. If you're using a plugin, check its settings to ensure this is the case.
Re-submit Sitemap: After making these changes, re-submit the sitemap to search engines. For Google, you can do this through Google Search Console.