Unable to login to the android stackoverflow app I'm not sure if this is the right place to ask.

I've the stackExchange Stackoverflow app on my android smartphone. I signed up to stackoverflow on my PC using my g+ account. 

The app's login screen doesn't offer g+ login. I dont't have a user/pass combo set up. How can I log-in to SO on my android phone?

thanks!
If you can't see Log in using Google, which is strange, use "Login using another OpenID".