Can't connect to packager on android

Hi. I finally found an important potential beta user who isn’t an iPhone user - so I’d like to get my expo app up and running on Android, but running into problems. TLDR; is when I run exp android I get the following error:

[exp] Possible Unhandled Promise Rejection (id: 0):
[exp] SyntaxError: JSON Parse error: Unrecognized token '<'
[exp] parse@[native code]
[exp] tryCallOne@http://packager.bj-7j3.marstall.reflyer-    mobile.exp.direct:80/./node_modules/react-native-scripts/build/bin/crna-entry.bundle?platform=android&dev=true&hot=false&minify=false:15291:14

When I hit that URL in a browser it works and returns a long javascript file.

I tried this on Genymotion as well as a device, same result. I tried on expo 19 + 20, same result. Works fine on iOS simulator and device.

Any insights?