Tax lien discovered

[Michael O'Byrne]

We are are flipping a house and just put it under contract with a buyer. Their title company just informed me the examiner found a recorded tax lien from a few years ago of over $23,000. The house has been sold twice since then, the most recent to me about a year ago. So why would my title company give me a commitment for title insurance with this lien on the books back when I purchased the property? If they missed it, are they liable? Just looking for possible explanations and options, thanks!!