I can’t recall a type for which approval was withheld by a regulator apart from some ex Soviet types.
I seem to recall that D.P. Davies, the then Chief test Pilot of the CAA predecessor, the Air Registration Board (ARB), found the control loads unacceptable for an average pilot suffering an outboard engine failure at a critical time. He was backed by the head of the ARB, Lord Brabazon, and the ARB would not grant the B707 approval.
Boeing fitted a larger fin and rudder in consequence.