What roles have you assigned to the newly created? In order to be able to login, at least one of the assigned roles have to match the security constraint defined in jbpm-console.war/WEB-INF/web.xml. Try to add the 'user' role to one of the new users and see if you can login afterwards.
You are right, thank you very much. I didn't specify any roles to my users.
Now it works!!