According to the law of contracts the following mistakes render a contract void:
This is a mistake as to the existence or ownership of the subject matter. Each party in the contract makes the same mistake which means that although each party understands the other’s intention both are mistaken about the same underlying fundamental fact.
This is a mistake as to the subject matter of the contract. It arises when parties misunderstand each other. No agreement arises due to lack of consensus.
This is a mistake as to the identity of one of the parties to the contract. Only one party
is mistaken and the mistake is induced the other party.