If you have the blue adapter, you could go to the settings and try checking the box for "Use BLUE adapter with OBDLink.."
That is the only way mine works. Note that frustratingly you must go into settings and check this box EVERY TIME you use the app, I often forget and then it never asks me for the blue cable and my alignment fails.
If you have an android tablet or chromebook you could try that too, there might just be issues with the bluetooth on the device you are using. It is good to disable the bluetooth connection to the Uconnect and anything else you have nearby that uses bluetooth (smart watch, etc) because it seems the OBDLink is greedy and wants to be the ONLY bluetooth thing you are connected to. Some have troubles with this some don't, might depend on the phone.
I switched to a $35 android tablet from best buy and had more luck than using my phone. Somebody else chimed in a few weeks ago that it worked good on a chromebook and I bet that would be the best, because then you have a big screen and keyboard which makes it way easier to look through a huge configuration dump or log file, etc.
I'm hoping to eventually get a cheap chromebook to use with AlphaOBD BUT there is always the windows version that can be installed on a regular laptop too which is technically cheaper route (don't tell my wife!)