I am getting an error when trying to add a user to group in JavaScript, here is my code below:
user = web.ensureUser("domain\\natalie");
membersGroup = web.get_siteGroups().getByName("site Members");
membersGroup.get_users().add(user);
userCollection = membersGroup.get_users();
context.load(user);
context.load(membersGroup);
context.load(userCollection);
context.executeQueryAsync(_onUserSucceed, _onFail);
I am getting the error: The parameter loginName cannot be empty or bigger than 251 characters.