App crashes once Restart Game clicked - ios

Question

App crashes when either player presses the Restart button. I tried adding an alert that shows up once Player2 accepts game reset and a new alert message that sends to Player1 in the OKAction line.
func handleReceivedDataWithNotification(notification:NSNotification){
let userInfo = notification.userInfo! as Dictionary
let receivedData:NSData = userInfo["data"] as! NSData
let message = NSJSONSerialization.JSONObjectWithData(receivedData, options: NSJSONReadingOptions.AllowFragments, error: nil) as! NSDictionary
let senderPeerId:MCPeerID = userInfo["peerID"] as! MCPeerID
let senderDisplayName = senderPeerId.displayName
if message.objectForKey("string")?.isEqualToString("New Game") == true{
let alert = UIAlertController(title: "Game Restart Request", message: "\(senderDisplayName) has requested to restart the game", preferredStyle: UIAlertControllerStyle.Alert)
let cancelAction = UIAlertAction(title: "No", style: .Cancel) { (acttion) in
}
alert.addAction(cancelAction)
let OKAction = UIAlertAction(title: "Yes", style: .Default) { (action) in
self.resetField()
let messageDicts = ["string":"RestartNow"]
}
alert.addAction(OKAction)
self.presentViewController(alert, animated: true) {
}
}else{
var field:Int? = message.objectForKey("field")?.integerValue
var player:String? = message.objectForKey("player") as? String
if field != nil && player != nil{
fields[field!].playerr = player
fields[field!].setPlayer(player!)
if player == "x"{
currentPlayer = "o"
}else{
currentPlayer = "x"
}
checkResults()
}
}
}
Here is where the alert is sent to when Player2 presses Accept/Yes:
#IBAction func newGame(sender: AnyObject, notification:NSNotification) {
let alertWait = UIAlertController(title: "Request Sent", message: "Waiting for other player to accept this request", preferredStyle: UIAlertControllerStyle.Alert)
self.presentViewController(alertWait, animated: true) {
}
let messageDict = ["string":"New Game"]
let messageData = NSJSONSerialization.dataWithJSONObject(messageDict, options: NSJSONWritingOptions.PrettyPrinted, error: nil)
var error:NSError?
let userInfo = notification.userInfo! as Dictionary
let receivedData:NSData = userInfo["data"] as! NSData
let message = NSJSONSerialization.JSONObjectWithData(receivedData, options: NSJSONReadingOptions.AllowFragments, error: nil) as! NSDictionary
let senderPeerId:MCPeerID = userInfo["peerID"] as! MCPeerID
let senderDisplayName = senderPeerId.displayName
if message.objectForKey("string")?.isEqualToString("RestartNow") == true{
let alertOK = UIAlertController(title: "Game Is Restarting", message: "\(senderDisplayName) has accapted game request", preferredStyle: UIAlertControllerStyle.Alert)
let OkayAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: { (alert:UIAlertAction!) -> Void in
self.resetField()
})
self.presentViewController(alertOK, animated: true, completion: nil)
}
appDelegate.mpcHandler.session.sendData(messageData, toPeers: appDelegate.mpcHandler.session.connectedPeers, withMode: MCSessionSendDataMode.Reliable, error: &error)
if error != nil{
println("error: \(error?.localizedDescription)")
}
}