What are the fundamental requirements for the admissibility of a lawsuit for damages arising from breach of contractual obligations?

The claim for compensation for breach of contractual obligations shall be dismissed if the plaintiff fails to prove the breach or that the defendant caused the damage. Furthermore, the plaintiff's acknowledgment that the other party fulfilled its obligations is a ground for the dismissal of the lawsuit. It is also considered a forfeiture of right if the necessary actions are not taken to demand the other party to rectify the defects or to terminate the contract.