Getting crash while using RNCallKeep for outgoing call in iOS app

I am trying to integrate CallKit for outgoing and incoming calls. While making outgoing call with CallKit, it crashes iOS app. Code as below:

RNCallKeep.startCall(uuid, extension, extension, 'generic', false);

Here all params are passed in required format. Though it crashes and gives this error in Xcode:

int main(int argc, char * argv[]) {
@autoreleasepool {
return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
}
}

Error Log:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[1]'
*** First throw call stack:
(0x1adb01114 0x1c1327cb4 0x1adb6b398 0x1adb76590 0x1ad9fc6a4 0x1ad9efa04 0x100b960c0 0x100b9b898 0x1cabddc80 0x1070efdb8 0x1070f15fc 0x1070ffa6c 0x1ada80c30 0x1ada7b0e8 0x1ada7a200 0x1c3b75598 0x1b0340004 0x1b03455d8 0x10068c264 0x1ad759598)
libc++abi.dylib: terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[1]'
terminating with uncaught exception of type NSException

Start at the RNCallKeep.startCall invocation and reproduce the outgoing-call path through the iOS CallKit integration using the Xcode exception log. Trace the arguments and the dictionary construction involved in this path to identify the nil value. Done means the crash cause is confirmed and outgoing calls complete without this exception.