iOS CoreBluetooth : centralManager:didConnectPeripheral / didFailToConnectPeripheral: not getting called

If you don't somehow retain the peripheral object that is delivered to didDiscoverPeripheral then it is released once this delegate method exits and you won't get a connection.

I suggest adding a property to track discovered peripherals

@property (strong,nonatomic) NSMutableArray *peripherals;

initialise this in viewDidLoad or init

self.peripherals=[NSMutableArray new];

And then add the peripheral to it in didDiscoverPeripheral

-(void) centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{    NSLog(@"Discovered peripheral %@",peripheral.identifier.UUIDString);    [self.peripherals addObject:peripheral];    [central connectPeripheral:peripheral options:nil];}

var peripherals = [CBPeripheral]()func centralManager(central: CBCentralManager, didDiscoverPeripheral peripheral: CBPeripheral, advertisementData: [String : AnyObject], RSSI: NSNumber) {    peripherals.append(peripheral)    bleManager.connectPeripheral(peripheral, options: nil)}

This is the Swift version.