I am indeed using adguard DNS.
But still doesn't explain why the app loading has issue while logging in by website on the phone internet browser has no issue?
giga website is built using Microsoft ASP .Net Framework Web Form (ASPX).
This is a legacy Web Application Framework where it adopt the Sever-sided Rendering concept.
While giga Android Mobile App is built as a hybrid App. Hybrid in a sense that it is using Web View that is rendering pages retrieve from ASPX server.
The new Dashboard page seems to making API calls to a brand new URL or domains.
How Adguard DNS block ads is by black listing domain name.
If giga App decide to makes API calls to a black listed domain, the connectivity will fail because the domain resolution failed.
When the app failed to retrieve data via API call from the blacklisted domain, the Apps may stuck at loading forever.
Another possibility is that the giga app is sending telemetry to some tracker website.
Since Adguard DNS also blocks Telemetry Tracker Domain name, this may answer why the App is not loading if Adguard DNS is activated.