"He liked my comment."
Translation:Il a aimé mon commentaire.
You have used the 3rd person present indicative of plaire - plaît.
If you are trying to say "My comment pleased him" then you would need the past participle of plaire which is "plu".
I believe the sentence would be "Mon commentaire lui a plu. " but it would be nice to have it confirmed by a native Francophone.
I also cannot comment on whether it would be an accepted answer even if I do have the French grammar correct.