https://github.com/mondora/asteroid/blob/7192311afc731ceffed7d11b6b005e764fcfbd7c/src/base-mixins/password-login.js#L14 Based on the documentation at https://docs.meteor.com/api/passwords.html#Accounts-createUser and current tests, the server method seems to expect the object sent in arguments of asteroid.createUser directly.