Looking at the code, it seems to be requiring both username and customer_id currently. It is supposed to return an error with something like "No username provided" if that is what the problem is. Though, it appears that the way it is written that error might not be making it back to you. You mind making a bug report here: https://q2developer.com/support/create?ticketType=Bug mention my name and I will look into it with you there.