error changing the member role

I started a new world, create alliance and now i got an invite, i try disband my own ally by changing my rank from cic to a lower level but it comes up everytime, no matter what i try, with :error changing the member role
The only way i can leave the ally is to create an other account or invite another player, promote that one to cic and then leave, but this should not be the way
please, anyone with a solution write me
cheers
harry