It doesn't have to be that he was actually caught in a scandal. It could be that the board was investigating some serious accusation, and he was not cooperative and forthright, which they might have no patience for.
I invented a saying to describe this common occurrence: "Sometimes the cover-up is worse than the crime."
We have a long history of indicting people for "lying under oath" and never indicting them for the actual issue they were interrogated about, which often is not an indictable offense, but rather something personally embarrassing.
And he probably wouldn’t approve unless there was a specific use case that he thought mandated an exception. Recent international news provide some inspiration.
I invented a saying to describe this common occurrence: "Sometimes the cover-up is worse than the crime."