Ionic - handle server maintinence error on login

I have an Ionic project with a Login page. Occasionally, the server API that the app is interacting with will go down for maintinence and you can only find out after logging in. A HTTP 200 status code will be passed back along with some web page which says something like “Site down for maintinence”. What is the proper way to handle this scenario from the API side and how should the Ionic (AngularJS) code respond? This is something we’re trying to figure out and communicate with the team that’s responsible for this.

One suggestion that I’ve seen is:

You could write an $http interceptor

Yeah, we talked to the network team. Supposedly, they’re going to return HTTP 302 so I’ll see how it turns out.