Please follow the below template, it will help us to help you!
Expected Behaviour:
I have a domain (example.com). I installed PH in the public cloud (oracle). Add blocking is working perfect! With my DNS provider I added the pihole as a subdomain (pi-hole.example.com) pointing to the public IP of my cloud compute instance.. It resolves.... so I should expect a fully working UI
Actual Behaviour:
The UI isn't working. If I browse to the public IP addess, everything is working flawlessly. See screenshot below: