Troubleshooting Unblocked URLs
If the Secure Access block page does not display when navigating to a URL you expect to be blocked, ensure that the policy rule with the destination list enabled is higher in order than other rules that the enrolled resources may be part of.
Wait up to five minutes before testing again after any changes are made to ensure that enough time has passed for the changes to be replicated throughout Secure Access.
If problems persist, clear the local browser cache on your machine. Alternatively, clear your machine's DNS cache—a reboot will accomplish this.
Also, check to see if you have a local—on-premise—proxy that is interfering.
Additionally, confirm that you have installed certificates. For more information, see Manage Certificates.