1. The plaintiff's claims against the defendants are all dismissed.

2. The costs of lawsuit shall be borne by the Plaintiff.

1. The gist of the plaintiff's assertion: The summary of the plaintiff's assertion that the plaintiff's claims for overdue rent, management fee, etc. in this case is as shown in the grounds for the claim.

2. Determination: The plaintiff's assertion cannot be accepted. The reasons are as follows.

(1) One of the parties to a bilateral contract may refuse performance of his/her own obligation until the other party provides performance of the contract.

However, this provision shall not apply where the obligation of the other party is not due.

(2) Where one of the parties is to perform in advance to the other party, if performance of the other party is substantially difficult, the main sentence of the preceding paragraph shall apply.

Article 536 of the Civil Code provides that the right of defense of the simultaneous performance is as follows.

As to the meaning of Article 536(2) of the Civil Act, the Supreme Court has a right to defense against simultaneous performance, on the ground that, even where one of the parties to a bilateral contract is liable to perform the obligation first to the other party, if there is a substantial reason to make it difficult for the other party to perform the obligation, the Supreme Court has a right to defense against non-performance. Here, “any reason to make it difficult for the other party to perform” refers to a change of circumstances where the debtor, who is liable to perform the preferential performance obligation, is unable to receive any counter-performance due to such reasons as the creditor’s credit unrefeasibleness or aggravation of property status after the formation of the contract, and thereby making the debtor perform the preferential performance obligation pursuant to the original terms and conditions of the contract go against the fairness and good faith principle, and whether there is such reason should be determined by comprehensively taking into account the circumstances of both parties. In addition, there is no reason to interpret that only the objective general circumstances occurred on the part of the creditor, such as credit unrefeasible or property deterioration, etc.