What is the ruling on praying behind someone who makes a mistake in reciting al-Fatihah by saying "al-'Alameen" instead of "al-'Alamin"?

Question:
Honorable Shaykh, the questioner says: The mu'adhdhin of a mosque sometimes leads the people in prayer. In his recitation of al-Fatihah, he says "al-'Alameen." I have pointed this out to him, but his tongue has become accustomed to it, and he does not believe in the wrong meaning. However, he pronounces it this way. Is his prayer valid, and is the prayer of those behind him valid?

Answer:
His prayer is not valid if he is able to correct it and does not, because "al-'Alameen" changes the meaning. This is a mistake that alters the meaning. If he is unable to correct it, his prayer is valid for himself, but it is not permissible for him to be an imam for the people. Yes.