Event Check In App on Android - can't log in

I installed the Marketo Event Check In app to our Google Pixel C.

When I try to log into the app, I receive the message "no connection detected. Please try again later" even though we're connected to wi-fi, the internet works, other apps work (including Marketo Moments).

In the google play store, when you hover over the app it says "No carrier Google Pixel C" but the app is compatible with the device. It looks like there's also one reviewer who had a similar problem.

I have an event tonight and would really like to be able to have the tablet there for check in, but I can't get past the log in screen. Has anyone run into this issue, and how did you resolve it?