CAS认证报The CAS server returned no response，求高手指教
javax.servlet.ServletException: org.jasig.cas.client.validation.TicketValidationException: The CAS server returned no response.
org.jasig.cas.client.validation.AbstractTicketValidationFilter.doFilter(AbstractTicketValidationFilter.java:155)
org.jasig.cas.client.authentication.AuthenticationFilter.doFilter(AuthenticationFilter.java:111)

root cause

org.jasig.cas.client.validation.TicketValidationException: The CAS server returned no response.
org.jasig.cas.client.validation.AbstractUrlBasedTicketValidator.validate(AbstractUrlBasedTicketValidator.java:181)
org.jasig.cas.client.validation.AbstractTicketValidationFilter.doFilter(AbstractTicketValidationFilter.java:132)
org.jasig.cas.client.authentication.AuthenticationFilter.doFilter(AuthenticationFilter.java:111)

------解决方案--------------------
把服务端的信息贴出来
------解决方案--------------------
这是在应用拿到ticket票据后，去CAS那里验证票据有效性时，没得到响应。查看CAS运行是否正常，尤其是CAS和应用的相关配置是否正确。