Hello i can't leave my island from skyblock

i wan't to be part from someone else island but when i do /is leave it says : youre not part of an island. but i do someone please help me i wan't to be part of mattiecool his island he's my friend

 

Im not an expert with the Skyblock plugin.
Yet, im pretty sure they just do /is invite [your name] then instead of trying to leave before joining, just do /is accept or /is join [inviters name] and that should put you through to his island.
Sorry about bad grammar, im at school.

 

they can't invite me tthat's the prbloem

 

Locking as inactive.
If this is still an issue feel free to make another thread.