I also am having problems. I have updated to 3.70, I am using correct cable (one with yellow label on bag) I did clean my audio port out of any lint i could with a toothpick. I shut doen every app running in the background on my phone, rebooted the phone, tried turning the cable around, re-opening the app, etc.
i can get it to connect but only rarely. maybe 1 in 10 times. sometimes I have trouble getting “Headphone volume OK” indicator to stay up. playing around with it it appears to be either a heaphone jack problem or a cable problem. apllting lateral pressure to headphone jack improves results. i am using iphone 6.
UPDATE: I wrapped a scrap of Kimwipes soaked in contact cleaner around a toothpick and swabbed my headphone jack on my phone vigorously. Now it works 100% of the time. so entirely dirty contact problem.