I'm talking about this one - Mobile_app - and I am using Moodle 2.3.3.
Enabled the mobile option on the server side. I installed the app, typed in my sites address, username and password. It just sits there showing a box with 'Authenticating' at the top and the spinning wheel. A few of us have tried it with various connections to the interweb and no difference.
I'm not entirely sure where to start diagnosing the problem. Does it require any specific support through the firewall (other than http and/or https which should work fine)?