@Abdu77 Like said above, install Emoji's extended, and for the 502 error, consult Leet since your forum isn't hosted at NodeBB, keep in mind that NodeBB requires some technical skills to keep online.
I meant to reply to this a day ago, but I forgot about it. Anyways. What you can consider is using the build in reward-essentials plugin to accomplish this. Make a group, and then make a rule in the rewards for >= add to group.