One of the main functions of an homeowners association (HOA) is to mediate disputes between neighbors. For that reason, they may restrict an owner’s right to sue their neighbor. You may not be successful in disputing that restriction because you’ve agreed to abide by those rules and the neighbor could reasonably expect to not be sued, citing protections of HOA rules.
This means that if you try to sue to establish adverse possession over your neighbor’s property, you might not be able to take the case to court and therefore, not gain legal ownership.