To block a specific site user from accessing all other sites over a site-to-site VPN, you have created a test rule. However, it seems that the rule is not functioning as expected. To resolve this issue, you may need to review and troubleshoot the rule configuration. Check if the rule is properly applied, the device is correctly identified, and the settings align with the desired blocking behavior. Adjustments or corrections to the rule may be necessary to successfully block the targeted user's access to all other sites.