You can go in Expert mode and use the domains_tool utility to check if your domain is resolved, the tool is present in Spark.
domains_tool -d onboarding.portal.arubainstanton.com
Your AP and firewall should use the same DNS for consistency. You might also need to add the full domains, do not assume the domain object will match all subdomains like in a regex URL object.
Check also that you have Hide NAT on, which I assume you have if Internet access works.
Is your policy in Strict Mode?
You might create an additional rule with Internet access from your AP for analysis and see what goes in there to fine-tune your firewall policy, unless it's against your security policies.
Also, fw ctl zdebug drop in Expert mode will show you what is dropped where if you don't see them in the logs.
HTTPS Categorisation will work with the Application/URL Filtering Blade activated, Domain objects are linked to the Firewall blade.
We don't use Domain objects in locally managed Spark so it's ideas.