Your permalink structure (for friendly looking URL’s) may not be not active.
- Go to Settings > Permalinks.
- Make sure it is not set to “Plain”. We recommend “Post name” (and this is what our sample content assumes you will be using).
- Click Save Changes even if no changes were made.
If you do this but the problem persists, your server may not be allowing WordPress to write the .htaccess file which enables a friendly URL structure. Return to Settings > Permalinks and look for manual instructions provided by WordPress below the Save button.