Why was the queen banned in Episode 24 of The Legend of Miyue?

Episode 24

Ying Si and Zhang Yi were talking about the situation in the world in the palace and cherished each other. When the good news came, Ying Si ordered to commend all the meritorious ministers. An envoy from Chu State came to Mi Shu and asked her to persuade Ying Si to return the land in Hanzhong. Wei Yan and Wei Shaojun came to see Mi Shu's joke, which angered Mi Shu even more. Mi Yue advised Mi Shu not to act out of anger. Mi Shu refused to listen to the advice and insisted on going to the King of Qin's palace. At the celebration banquet, Mi Shu accused Zhang Yi of being a villain and advised Ying Si to eliminate the traitors in the court and restore old friendship with Chu. Ying Si was furious and ordered Mi Shu to go back to the palace to think about her fault. During the dispute, Mi Shu had fetal gas. Ying Si handed over the harem affairs to Wei Yan and issued a ban on Mi Shu. Mi Yue met Meng Ying in the stable, and Meng Ying persuaded her to sleep with him. Mi Yue said that there was someone else in her heart. Ying Si received an urgent letter from Mrs. Ying and rushed to the palace in the northern suburbs. Wei Yan took advantage of Ying Si's absence in the palace and sent someone to arrest Wei Ran for theft.