Can't throw a party in Sims 3

Try resetting the sim with resetsim firstname lastname or try to move out and back in via edit town.

I've tried that but it didn't work

try edit town

1  move the sim out and back in and or edit town

2 save a copy of your sim to the library delete the clipboard image one in the top left then move your sim back in BUT before doing this when you launch your game use the save as new name to keep your original game left alone and as it is and with the save as new name you can see if things go well etc with that latter suggestion 2  though your sim will be starting with new wishes and building up friendships up around the town and uni friends if they go back to uni

Hey guys! I was having the same problem with my people on Sims 3. After my sim got invited to a party and tried to attend, my sim was unable to go for some reason and never went. Ever since then, the option to throw a party via cell phone was grayed out. I think found something that worked after trying everything on other forums.

I saved my sim's game and went to play on the other sim who invited my sim to a party and made him throw a party (it was not grayed out for him luckily) Then after it said the party was a success, I saved it and went back to my original sim game. I checked to see if I was able to throw a party with my original sims after this and yesss it worked!! Hopefully this is a fix for everyone else. Goodluck!!