I don’t see any way to change the “primary domain” in app settings. It is currently set to my-app.meteorapp.com instead of my-domain.com.
At the moment, it is not possible to make this change in the Galaxy dashboard. Technically, it would be possible to implement this feature in the future, but it would not be something that could be done in the short term.
Whenever you want to get faster responses from our support team, you can always open a ticket at https://beta.galaxycloud.app
As replyed [here]Galaxy: Error in OAuth Server: redirectUrl (https://my-domain.com) is not on the same host as the app (https://my-app.meteorapp.com/) - #3 by italojs), you should set ROOT_URL from envs but not from setting.json