Azure Web App default hostname being used instead of domain

[TonyLaw12 (Tony Law)]

Found the solution in case anyone else is struggling. The article linked in this thread is what has fixed it.

Umbraco 15 behind Azure Front Door

Has anyone here setup Umbraco 15 yet on an Azure app service hosted behind a an Azure Front Door implementation? Our infrastructure terminates the SSL / DNS on the front door route, and routes the traffic to the correct app service over a private link, so no public access is permitted to the app service, and nor does it know about the public facing URL. This setup works fine for Umbraco 13, but on 15 (And we noticed it on 14 as well), when you access the back office login page it performs a re…