How to access inner objects in Thymeleaf?

I am trying to Iterate a List if Users using thymeleaf,

My User object is like this

public class User implements java.io.Serializable {

    private Integer userId;
    private Department department;
    private String email;
    // setters and getters etc
}

and department object is like this

public class Department implements java.io.Serializable {

    private Integer departmentId;
    private String name;
    // setters and getters etc
}

in thymeleaf I do this

<tr th:each="user : ${users}">
    <td th:text="${user.email}"></td>
    <td th:text="${user.department.name}"></td>
</tr>

and I am getting this error

org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "user.department.name"

if I use only user.email, there is no issues.

So how to access inner objects in in Thymeleaf EL? (In my case user.department.name)