Plural is not valid with the French translation. "Kisses" = baisers a kiss = un baiser.
Although "Un baiser" is just a word and not a sentence, giving a plural shows that the translator interpreted the meaning. If so, it would have been better to ask the person who gave the translation to be more precise.
Finaly, I don't think "Kisses!" fits with "Un baiser" in any case.