I am experiencing the same issue with using the connectpro:// URL on Android as jcooper9099. When using connectpro://servername/meeting/ the app gets stuck forever. However, using connectpro://https://servername/meeting loads up the meeting join screen with the URL loaded into the meeting URL textbox.
There must be something I'm not passing correctly because if I connect to the meeting URL via the web browser and click on the Launch Adobe Connect Mobile link, it loads correctly. It's only when crafting my own URL that the problem appears.