Contractor Responsibility

Hey seasoned recruiters, I could use your insights! As a contractor, I recently invested a lot of time in finding the right candidate. However, after extending the offer, the HR manager took over the process. It’s now been 2.5 weeks, and the candidate still hasn’t officially signed. My question is: at what point does a recruiter’s responsibility end? If the candidate ultimately doesn’t sign, is that on the recruiter? Thanks for your thoughts!