Im not sure about the limit, actually i think is 1, some days ago i sold my island to someone and i wanted to create a new one and i cant do it, may i get my island create reset? i cant make an island right now. Thanks. -ultra
Probably because you still have an island. [The one you sold] I think you need to delete the one you sold before making new one, not sure tho.
And what exactly happens when you type /is, or try to create an island? Is there a message that shows up, can you tell me or make screenshot?
Well i dont know much to help you but in this case you should click staff-->Skyblock And ask the admins in there they might help in this case if you don't get help from this.
@Ultramutrix are you invited to that island or can you place blocks on it? If yes try /is leave and then try creating an island again.
Do you get that message with all of the 4 commands? And can you place blocks on the island that you sold? If you cannot use any of these commands and if you are not is invited to island you sold, it is a bug and you should make a bug report.