尝试连接VPN时出现此错误，我尝试了Internet上的所有内容，但没有运气。

  

这是我的代码

    private var vpnLoadHandler: (Error?) -> Void { return
        { (error:Error?) in
            if ((error) != nil) {
                print("Could not load VPN Configurations",error)
                return;
            }
            let p = NEVPNProtocolIPSec()
            p.username = "vpnuser"
            p.serverAddress = "111.11.11.11"
            p.authenticationmethod = .sharedSecret

            let kcs = KeychainSwift()
            kcs.set("####",forKey: "SHARED")
            kcs.set("####",forKey: "VPN_PASSWORD")
            p.passwordReference = kcs.getData("VPN_PASSWORD")
            p.sharedSecretReference = kcs.getData("SHARED")
            p.useExtendedAuthentication = false
            p.disconnectOnSleep = false
            self.vpnmanager.protocolConfiguration = p
            self.vpnmanager.localizedDescription = "Contensi"
            self.vpnmanager.isEnabled = true
            self.vpnmanager.saveToPreferences(completionHandler: self.vpnSaveHandler)
    }
}