Question: How does the PIN code for Airplay and Miracast work?
Answer: It's logical. The PIN won't change until it has been used. Once used, the code will remain the same until all the active streams disconnect. Once all streams are disconnected it will change the code after 15 minutes.
Note: You must input all 8 numbers of the Miracast PIN code for it to work. You must include all the leading 0's.