[SOLUTION] Had this issue, none of the reconnects worked, new USB wouldn’t work, new updates didn’t work, also tried “Halloweenhamster” solution and it didn’t work so this for everyone else. maybe I just got lucky but haven’t had problems since. Also..using iOS with an updated 8+
Turn everything off
Switch AC to WiFi mode
Turn on AC and wait a few seconds
Connect phone WiFi to “Mavic” network
Use guidelines with phone to fly...
Once I turned everything off and switched back to RC mode on the AC-it worked.
Hope it works for you, like I said, may have been lucky