in the authenticate user server behavior code, the UserID column is being used for the password:
"columns" => explode($WA_Auth_Separator,"UserEmail".$WA_Auth_Separator."UserID"),
Double click the authenticate user server behavior, go to the second page.
select the UserID column from the columns list and click the minus button to remove it.
then click the pluss button and select the Password column, net to value click the lightning bolt and select the userpassword Form Element.