Error Initializing One Connect and can't connect to VPN Server

[aannurwahidi7]

I am a new developer, currently building a new VPN with One Connect SDK in iOS, but I have a problem when I'm trying to connect to VPN server it doesn't do anything, in log before connecting VPN server it says :

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: PlatformException(-4, IPC failed, IPC failed, null) #0 StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:648:7) #1 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:334:18) <asynchronous #2 OpenVPN.initialize.<anonymous closure> (package:oneconnect_flutter/src/vpn_engine.dart:123:13) <asynchronous>

Please help me, Thank you.