If you're experiencing a 404 error when trying to access posts on your WordPress site, there are several potential causes and solutions:

1. Permalink Settings:

   • Go to your WordPress dashboard > Settings > Permalinks.
   • Check if your permalink structure is set correctly. Sometimes, resetting permalinks can fix this issue. Simply re-save your preferred permalink structure.

2. Check for .htaccess Issues:

   • Your .htaccess file may be corrupted or misconfigured. You can regenerate it by going to Settings > Permalinks and clicking "Save Changes" without making any changes.

3. Plugin Conflicts:

   • Deactivate all plugins and check if the issue persists. If not, reactivate each plugin one by one to find the conflicting plugin.

4. Theme Conflicts:

   • Temporarily switch to a default WordPress theme (like Twenty Twenty-One) and check if the issue persists. If it doesn't, the problem might be with your current theme.

5. Rebuild Permalinks:

   • You can try rebuilding the permalinks by going to Settings > Permalinks and clicking "Save Changes" even if you haven't made any changes.

6. Check for Post Status:

   • Ensure that the posts you're trying to access are published and not in draft or private status.

7. Check for Typos in URLs:

   • Make sure there are no typos or extra spaces in the post URLs.

8. Check .htaccess File Permissions:

   • Ensure that the .htaccess file has proper permissions. It should typically be writable by the server.

9. Check Server Configuration:

   • In some cases, server misconfigurations can cause 404 errors. You might need to consult with your hosting provider or server administrator to investigate further.

10. Check for Page/Post Conflict:

• If you have a page and a post with the same slug, this can cause conflicts. Make sure that your post slugs are unique.

11. Check for Custom Rewrite Rules:

• If you or a plugin have added custom rewrite rules, they might be causing conflicts. Review any custom code related to rewrites.

12. Flush Browser Cache:

    • Sometimes, browsers can cache incorrect information. Try accessing the posts in a different browser or after clearing the cache.

13. Check for Server Cache:

    • If you're using server-level caching (like through a caching plugin or a CDN), it might be causing the 404 errors. Try clearing the cache.

Remember to always back up your site before making any significant changes, especially if you're going to edit or modify important files like the .htaccess. If you're uncomfortable making these changes yourself, consider seeking help from a developer or your hosting provider's support team.