can't RSVP to a group

[dapiot holmp]

Hi  I have tried RSVPing to a group   it's saying it's full when it is not  

curl "https://api.meetup.com/2/rsvp/"  -k -F "event_id=231962061" -F "rsvp=no" -F "key=__________" 

{"details":"There are not enough spots for your rsvp","code":"too_few_spots","problem":"Your command could not be completed"}  

I don't know if it's because since I managed to RSVP yes and then RSVP no, now it says "change". But I definitely was able to RSVP yes or no and change from yes to no to yes e.t.c.  So it was working but suddenly not so.

Note- sorry if this appears twice. I clicked post the first time and it didn't appear.