I ran into this issue today so I thought I'd share.

According to the docs:

When a class initializer fails to initialize a type, a TypeInitializationException is created and passed a reference to the exception thrown by the type's class initializer. The InnerException property of TypeInitializationException holds the underlying exception. TypeInitializationException uses the HRESULT COR_E_TYPEINITIALIZATION, that has the value 0x80131534. For a list of initial property values for an instance of TypeInitializationException, see the TypeInitializationException constructors.

This error occured in my project because I had elements in my App.config file that were not recognized. This is most commonly caused by using an invalid setting in the config file.

Once I removed the invalid elements, everything worked fine again.

If you are having this problem, double-check your App.config file and make sure you haven't included anything wrong.

Happy debugging, I hope this solves your problem.