How can you challenge a hold harmless agreement that you do not believe was signed legally?

To challenge a hold harmless agreement you believe was not signed legally, you should first gather evidence indicating that the agreement lacks the necessary elements of a valid contract, such as mutual consent, capacity, and consideration. Review the circumstances of the signing to identify any coercion, fraud, or misrepresentation. Consult with an attorney to assess the specifics of your situation and determine the best legal strategy, which may include filing a motion to invalidate the agreement in court. Lastly, ensure you keep a record of all relevant communications and documents related to the agreement.