Callback is traversed but isn't called

I have a bit of code that looks like this:

public void ManageServerCall(SomeClass someClass)
{
	ServerCaller.ServerCall(someClass.field, ServerCallCallback);
}

public static void ServerCall(string field, Action callback)
{
	data = // some data building
	Communicator.Send(data, exception => { if (exception == null) { callback(); } });
}

I’ve even gone over this with a fine tune debugger. When I make the server call, it builds the data, it sends the request, it calls the response callback (The lambda method in the second parameter slot), it checks the exception, goes over the callback but doesn’t go into it.
I’ve tried many ways of going about this, I’ve tried embedding debug logs in several places, I’ve tried giving a lambda method as a ServerCallCallback. It isn’t a CoRoutine. I’ve checked that too.

Does anyone have an idea why isn’t it being called?

The answer is waiting approval by a moderator.
You’re right. I found it. The callback was not the one I assumed it was and it took me a while to find out where it was different. So this is completely not a “Unity” issue and this whole question can be chucked as far as I’m concerned.

Thanks for putting up with me.