IOS Platform Error: flutter_callkeep/SwiftCallKeepPlugin.swift:152: Fatal error: Unexpectedly found nil while unwrapping an Optional value

[ldev1211]

My code:
final callKeepBaseConfig = CallKeepBaseConfig(
appName: 'Done',
androidConfig: CallKeepAndroidConfig(
logo: 'ic_launcher',
notificationIcon: 'ic_launcher',
accentColor: '#34C7C2',
),
iosConfig: CallKeepIosConfig(
iconName: 'Icon',
maximumCallGroups: 1,
handleType: CallKitHandleType.generic
),
);
final config = CallKeepIncomingConfig.fromBaseConfig(
config: callKeepBaseConfig,
uuid: call.id!,
contentTitle: call.remote_display_name,
hasVideo: false,
handle: call.direction,
callerName: "HIHI",
extra: {"data1":"ddwwd","data2":'dwqddddd'},
);
await CallKeep.instance.displayIncomingCall(config);

When I run app in real device ios platform, i got a message:
flutter_callkeep/SwiftCallKeepPlugin.swift:152: Fatal error: Unexpectedly found nil while unwrapping an Optional value
flutter_callkeep/SwiftCallKeepPlugin.swift:152: Fatal error: Unexpectedly found nil while unwrapping an Optional value

• thread How to use this plugin??? #1, queue = 'com.apple.main-thread', stop reason = Fatal error: Unexpectedly found nil while unwrapping an Optional value
  frame #0: 0x000000019fa7ca3c libswiftCore.dylib_swift_runtime_on_report libswiftCore.dylib:
  -> 0x19fa7ca3c <+0>: ret
  libswiftCore.dylib: 0x19fa7ca40 <+0>: b 0x19fa7ca3c ; _swift_runtime_on_report libswiftCore.dylib:
  0x19fa7ca44 <+0>: adrp x8, 366325
  0x19fa7ca48 <+4>: ldrb w0, [x8, #0x994]
  Target 0: (Runner) stopped.`

What should I do?