If a domain appears to be blocked by your policy, but the query log isn’t showing any related entries, you can create an “open policy.” An "open policy" is a policy with no restrictions from categories, threats, etc. The idea is to apply this policy and see if the domain becomes accessible. If it loads without issues under the open policy, this can be an indication that the block is indeed due to the established policy settings.

You can then begin adding in restrictions until you identify what specific setting is causing it to be blocked. You may need to add an exception (Allow) to override that specific domain if you want to keep the category that is blocking it enabled.

Has anyone tried this method or found any other effective ways to troubleshoot this instance?