Disconnected from MQTT, error: Optional(Error Domain=MGCDAsyncSocketErrorDomain Code=8 "Error in SSLSetCertificate" UserInfo={NSLocalizedDescription=Error in SSLSetCertificate})

I am trying to connect with MQTT with DigiCert G2 .crt certificate from https://zcusa.951200.xyz/en-us/azure/security/fundamentals/azure-ca-details?tabs=root-and-subordinate-cas-list#root-certificate-authorities, I am getting this error.

Disconnected from MQTT, error: Optional(Error Domain=MGCDAsyncSocketErrorDomain Code=8 "Error in SSLSetCertificate" UserInfo={NSLocalizedDescription=Error in SSLSetCertificate})

pod 'CocoaMQTT', :modular_headers => true pod 'MqttCocoaAsyncSocket', :modular_headers => true

Anything which I am doing wrong here?

import Foundation
import CocoaMQTT

class MQTTManager: CocoaMQTTDelegate {
    func mqttDidDisconnect(_ mqtt: CocoaMQTT, withError err: (any Error)?) {
        print("Disconnected from MQTT, error: \(String(describing: err))\n")
    }
    var mqtt: CocoaMQTT!
    func mqtt(_ mqtt: CocoaMQTT, didPublishAck id: UInt16) {
        print("Published message with ID: \(id)")  }
    func mqtt(_ mqtt: CocoaMQTT, didSubscribeTopics success: NSDictionary, failed: [String]) {
        print("Subscribed to topics: \(success)")  }
    func mqtt(_ mqtt: CocoaMQTT, didUnsubscribeTopics topics: [String]) {
        print("Unsubscribed from topics: \(topics)")
    }
    func mqttDidPing(_ mqtt: CocoaMQTT) {
        print("Pinged!")}
    func mqttDidReceivePong(_ mqtt: CocoaMQTT) {
        print("Ponged!") }
    func mqttDidDisconnect(_ mqtt: CocoaMQTT, withError err: (Error?)?) {
        print("Disconnected from MQTT, error: \(String(describing: err))")
    }
    func mqtt(_ mqtt: CocoaMQTT, didConnectAck ack: CocoaMQTTConnAck) {
        if ack == .accept {
            print("Connected to the MQTT broker!")
            // Subscribe to a topic only after a successful connection
            subscribeToTopic(topic: "your-topic")
        } else {
            print("Failed to connect to MQTT")
        }
    }
    func mqtt(_ mqtt: CocoaMQTT, didPublishMessage message: CocoaMQTTMessage, id: UInt16) {
        print("Published message: \(message.string ?? "") with ID: \(id)")
    }
    func mqtt(_ mqtt: CocoaMQTT, didReceiveMessage message: CocoaMQTTMessage, id: UInt16) {
        if let messageString = message.string {
            print("Received message on topic \(message.topic): \(messageString)")
        }
    }
    func connectMQTT(sasToken: String, assignedHub: String, registrationId: String,uuid: String, certificate: String, otp: String,deviceKey: String, modelId: String) {
        mqtt = CocoaMQTT(clientID: registrationId, host: assignedHub, port: 8883)
        print("Attempting to connect to MQTT broker... with client ID:\(String(describing: mqtt)) & \(mqtt.clientID)")
        mqtt.delegate = self
        mqtt.username = "\(assignedHub)/\(registrationId)/?api-version=2021-04-12";
        mqtt.password = sasToken;
        let certPath = Bundle.main.path(forResource: "DigiCertGlobalRootG2", ofType: "crt")!
              let certData = try? Data(contentsOf: URL(fileURLWithPath: certPath))
              let sslSettings: [String: NSObject] = [
                  kCFStreamSSLPeerName as String: assignedHub as NSObject,
                  kCFStreamSSLCertificates as String: [certificate] as NSObject
              ]
        mqtt.allowUntrustCACertificate = true
        mqtt.sslSettings=sslSettings
        mqtt.connect()
    }
}