What ist exact meaning of this exception?

org.jboss.seam.RequiredException with message: "In attribute requires non-null value: manager.value

I have code

@Name("manager")
@Scope(ScopeType.CONVERSATION)
public class Manager {

 @In(create=true)
 @Out(required=false)
 private Value value;

 @Factory("value")
 public void initValue() {

 value = new Value();
 }

 <h:inputText value="#{manager.value} />

Caused by org.jboss.seam.RequiredException with message: "In attribute requires non-null value: manager.value"

org.jboss.seam.Component.getValueToInject(Component.java:2042)
org.jboss.seam.Component.injectAttributes(Component.java:1481)
org.jboss.seam.Component.inject(Component.java:1302)