Why was the archbishop against the convent and Sor Juana?

Archbishop Antonio Nunez de Miranda was Sor Juana Ines de la Cruz's confessor; he was opposed to her work at the convent because he felt her writing went against Biblical teachings.
De la Cruz went into the convent when she was 16 because she wanted a life of quiet study and reflection. This was in contrast to her years as a lady-in-waiting at the Spanish court. However, Archbishop de Miranda was often opposed to De la Cruz's work in the convent. He believed that women's association with the devil and worldly lusts meant that they were temptations for men and that they needed to be contained. For him, convents were places for women to remain secluded in ignorance. For De la Cruz, a convent was a place to learn, study, and grow.
Later in life, De la Cruz would say that if the Archbishop had known that kind of writing she'd do, he would have made sure she married someone instead of becoming a nun. She ended up taking a new confessor because of his public statements and personal beliefs against her.