You can also try these following methods, The first method to remove Device Management is via iPhone Settings, this is the easiest way to remove device management on iPhone is with the passcode. The second method is to delete Device Management through Jailbreak iPhone, Jailbreak iPhone can delete device management without password, but it would cause lots of problems such as virus attacks, data loss, and device errors. If you can accept it, then have a try. The third method is to use MagFone iPhone Unlocker to remove MDM within 2 steps: Fire up MagFone and connect iPhone to computer first, then remove MDM Profile from iPhone without password. I sincerely wish these method will help you.