我在修改自己app用户的密码时调用环信修改密码出错

{"error":"duplicate_unique_property_exists","timestamp":1478745455459,"duration":0,"exception":"org.apache.usergrid.persistence.exceptions.DuplicateUniquePropertyExistsException","error_description":"Application null Entity user requires that property named username be unique, value of 182********1 exists"}
 
 
我在修改自己app用户的密码时调用环信修改密码出上边这个错误是什么情况