You have a quality issue in your part due to that the two bodies are not lined up properly. This is probably due to the way you have created them. Attached you will find a quick fix as the input geometry only are unparameterized bodies. Have a look to the attached movie file with comments.
I hope this will help you
Your solution was very helpful! Thank you for the video. It helped me very much!
Also thanks to Cesare, ScottFelber for comments and solution!