The paradox ( formulated by Wittgenstein) :

"This was our paradox: no course of action could be determined by a rule, because any course of action can be made out to accord with the rule".

The first solution :

A language-user's following a rule correctly is not justified by any fact that obtains about the relationship between his candidate application of a rule in a particular case and the putative rule itself (as for Hume the causal link between two events a and b is not determined by any particular fact obtaining between them taken in isolation); rather, the assertion that the rule that is being followed is justified by the fact that the behaviors surrounding the candidate instance of rule-following (by the candidate rule-follower) meet other language users' expectations.

Short rebuttal:

This does not explain the observation that people can keep playing a language game despite not following the rules properly ( w.r.t each others expectations ). Equating an understanding of rule following with expectation of users reduces the complexity of rule following in a language game. This solution isn't satisfactory.

The second solution :

McDowell argues that Wittgenstein does present the paradox (as Kripke argues), but he argues further that Wittgenstein rejects the paradox on the grounds that it assimilates understanding and interpretation. In order to understand something, we must have an interpretation. That is, to understand what is meant by "plus," we must first have an interpretation of what "plus" means. This leads one to either skepticism—how do you know your interpretation is the correct interpretation?—or relativity, whereby our understandings, and thus interpretations, are only so determined insofar as we have used them.

Short rebuttal:

This solution also suffers from a similar problem. People easily switch between one language game to another, in which case interpretation and understanding are assimilated. Furthermore, I don't see how we don't interpret and understand rule following simultaneously in a language game, especially when the "moves" are complicated.