It marked Henry's first game in charge of ASM.
Henry told a press conference: "I want to keep talking about the positives rather than the negatives, otherwise we cannot move on.
"We had opportunities, but we were 1-0 down at half-time and after Samuel was sent off it got even harder, but we tried to continue playing, even with 10 men.
"We tried to put something in place that worked from the beginning, but we let in a goal that I do not need to describe. It was a human error and I do not need to overwhelm anyone."