While trying to execute one of the test methods, it fails with the following exception:
System.InvalidOperationException: _5MSCAPTVvCE53ofLWmErNt4nvNO_._n18Eb1DF6eMsCxaJ9Z8eBYuIm18_ is inaccessible due to its protection level. Only public types can be processed.
Looking at the stack trace it is confirmed that, error is originating while mocking an object using Isolate.Fake.AllInstances method. which looks something like this.
Also verified, all the classes and its members are of type public.