AutoFixture with NUnit and AutoData throws TargetParameterCountException

In my unit test project I have installed AutoFixture (v3.40.0), NUnit (v2.6.4.) and AutoFixtrue.NUnit2(v3.39.0).
I'm using AutoData attribute on one of the dummy test cases

[Test, AutoData]
        public void IntroductoryTest(
            int expectedNumber)
        {               

        }

, but when running the test I get the

System.Reflection.TargetParameterCountException : Parameter count mismatch.
   at System.Reflection.RuntimeMethodInfo.InvokeArgumentsCheck(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at NUnit.Core.Reflect.InvokeMethod(MethodInfo method, Object fixture, Object[] args)
   at NUnit.Core.TestMethod.RunTestMethod()
   at NUnit.Core.TestMethod.RunTestCase(TestResult testResult)

Is there anything I haven't installed or I'm missing?