On skyblock I can't type ANY commands... /is /is create /is leave /is join and all the others it always says "an internal error has occured while attemting to preform this command" I've seen this before but i've never had this problem.
I'll try my best, I don't know much about skyblock. Have you tried /is delete(If you want to start over)? Did this happen one time you logged on, or is this everyday?
I have made several threads about this in the past. We cannot fix it, it is the developer of the plugin's job too. I have had this for 5 mths, I have been doing Hellblock challenges ever since. They are all the same challenges and I am always there too help you.
Send an email to [email protected] with the information you have provided here. You will probably not get an immediate response, so just send an email with the same message once a week.