According to the Civil Procedure Law of People's Republic of China (PRC), the application for retrial must be signed or sealed by the applicant. If the plaintiff fails to sign, and the retrial application does not conform to the legal form, the court may reject it according to law. In addition, if the facts, reasons and evidence in the application for retrial are insufficient to support retrial, the court may also reject it according to law. Therefore, the plaintiff's failure to sign the retrial application can be dismissed.