If you're encountering a "404 Error" when trying to access the WordPress admin login page, it could be caused by several factors. Here are steps to troubleshoot and resolve this issue:

1. Verify URL and Typing Errors:

   • Make sure you're using the correct URL to access the login page (usually http://example.com/wp-admin). Additionally, ensure there are no typos in the URL.

2. Clear Browser Cache and Cookies:

   • Cached data in your browser can sometimes cause login issues. Clear your browser's cache and cookies and try accessing the login page again.

3. Check .htaccess File:

   • Incorrect rules in your .htaccess file can sometimes lead to a 404 error. Try temporarily renaming or removing the .htaccess file and see if you can access the login page.

4. Check File Permissions:

   • Ensure that the files and directories in your WordPress installation have the correct permissions. The wp-admin directory should typically have permissions set to 755, and files inside it should be set to 644.

5. Verify wp-login.php File:

   • Make sure the wp-login.php file in your WordPress root directory is not missing or corrupted. If it's missing, you might need to restore it from a backup or reinstall WordPress.

6. Check for Theme or Plugin Conflicts:

   • Deactivate all plugins and switch to a default theme (like Twenty Twenty-One). If you can access the login page, it indicates a conflict with either the theme or a plugin.

7. Use a Default Permalink Structure:

   • If you're using custom permalinks, switch to a default structure temporarily and try accessing the login page.

8. Check Server Configuration:

   • Contact your hosting provider to ensure there are no server-level restrictions or configurations causing the issue.

9. Inspect Server Logs:

   • Review your server's error logs for any specific information about the 404 error. This can provide more context on what's causing the issue.

10. Check for ModSecurity Rules:

    • If your server has ModSecurity enabled, it might be blocking certain requests. Contact your hosting provider to review ModSecurity rules.

11. Reinstall WordPress Core Files:

    • If none of the above steps work, consider reinstalling the core WordPress files. Make sure to keep a backup of your site before doing this.

12. Contact Hosting Support:

    • If you're still unable to resolve the issue, contact your hosting provider's support team. They can review server configurations and logs to identify and resolve the issue.

Remember to always back up your site before making any significant changes. This allows you to revert back if any further issues arise.