labrad manager shutting down

[pppplin]

Hi,
When I try bin/labrad to start manager, I got the error message on
some listeners failed to start: java.lang.NullPointerException, java.lang.NullPointerException, any suggestions on how to fix this issue? Thanks.
full error message:
16:23:26.099 [main] INFO org.labrad.manager.Listener - shutting down
16:23:26.206 [main] INFO org.labrad.manager.Listener - shutting down
Exception in thread "main" java.lang.Exception: some listeners failed to start: java.lang.NullPointerException, java.lang.NullPointerException
at org.labrad.manager.Listener.(Listener.scala:114)
at org.labrad.manager.CentralNode.(Manager.scala:68)
at org.labrad.manager.Manager$.main(Manager.scala:212)
at org.labrad.manager.Manager.main(Manager.scala)

[pppplin]

More details:
manager connected successfully for the first time, but when I shut it down and try to connect again, the above error occurs.
Just found that this can be solved by restarting the terminal.