Birthday party - compliment the birthday sim

I don't remember seeing that requirement on any of my parties (and I got them all gold multiple times). Also I don't remember I've ever seen "compliment sim" in my chat options.

But the task is always general, for example if a task is tell a joke, you can tell any joke.
in this case any chatty compliment option should be correct. Compliment outfit, flatter, express admiration and such should do. Try them all, I seriously didn't have this task on my parties so can't help more.

EDIT:
Oops, compliment outfit doesn't work? Then IMO it's a bug.

I had three parties so far & they all ask for that as mini goals. Just my luck. :( Because of that, I keep missing out on gold medal.
Have anyone else got this action and know the fix?

I created a guide about parties, maybe you can prepare some of the additional goals. The additional goals varies each time you trow a party. http://sims-online.com/sims-4-social-events-throwing-party/

Yep, already read the guide you've posted before I post my thread. Your guide is good but it's kinda a general guide. Not what actions you need to do to complete each of the mini-games when you hold the event. Thanks for the guide though. :)

Compliment Outfit and Heartfelt Compliment both work.

compliment appearance or compliment outfit has worked for me

That's so weird. Have tried Compliment Outfit numerous times to no effect. Will try Heart Compliment & Compliment Appearance next time. BTW, can't remember but are those 2 options under Friendly?

Heartfelt compliment is under friendly. I think complement appearance and outfit are under romantic (I THINK; it's still early, need moar coffee), so I try to avoid that one except for Sims involved with each other.

Thanks :)

I've never had any luck with "Compliment Outfit" counting toward the goal, but the other "Compliment X" (Heartfelt Compliment, Compliment Appearance, etc.) options have worked for me.