Ble not connect in android 5.0 or more -

when connect ble device android phone in kitkat it's working fine. in case of lollipop or android 5.0 scanning work's , device connected. after 5-10 seconds it's automatically disconnected. why happening don't understand. please me , reply me possible. code is,

bluetoothlescanner = mbluetoothadapter.getbluetoothlescanner();         scancallback mscancallback=new scancallback() {             @override              public void onscanresult(int callbacktype, scanresult result) {               log.i("callbacktype", string.valueof(callbacktype));               log.i("result", result.tostring());               bluetoothdevice btdevice = result.getdevice();               adddevice(btdevice);               }         }; 

connect code that

public boolean connect(bluetoothdevice device) {      // if (mbluetoothadapter == null || address == null) {     // log.w(tag,     // "bluetoothadapter not initialized or unspecified address.");     // system.out.println("devices mbluetoothadapter && address null ");     // return false;     // }     //     // final bluetoothdevice device =     // mbluetoothadapter.getremotedevice(address);      if (device == null) {         log.w(tag, "device not found.  unable connect.");         // system.out.println("devices  devices null ");         return false;     }     // want directly connect device, setting     // autoconnect     // parameter false.     mbluetoothgatt = device.connectgatt(this, false, mgattcallback);     log.d(tag, "trying create new connection.");     // system.out.println("devices trying create new connection.");     mbluetoothdeviceaddress = device.getname();     mconnectionstate = state_connecting;      try {         thread.sleep(20);     } catch (interruptedexception e) {         e.printstacktrace();     }      return true; }