NRF.setAdvertising 'name' and 'iBeacon'

Thank you for the hint ... so I have changed it to

const adv = [ 0x1e, 0xff, 0x4c, 0x00, 0x12, 0x19, 0x00, key[6], key[7], key[8], key[9], key[10], key[11], key[12], key[13], key[14], key[15], key[16], key[17], key[18], key[19], key[20], key[21], key[22], key[23], key[24], key[25], key[26], key[27], key[0] >> 6, 0x00, {}];
NRF.setAdvertising(adv, {interval:1500,name:ble_name,showName:true,discoverable:true,connectable:false,scannable:true});

Although there is no error or message the device seems to fall back so I can connect via IDE ... it does not advertise like I want it to. I am a little out of ideas now.