Error XMPPServlet - XMPPWebSocket deliver java.lang.IllegalStateException: Blocking message pending 10000 for BLOCKING

I keep getting this message error blocking message pending 10000 blocking in error.log of Openfire.

And dont take this following sentence too seriously - just some observations : I dont know exactly but it looks like when the number of current users increase ,there are more of this error . I suspect that this is also the reason make the chat server sometimes can be connected to and sometimes not (I am talking about the situation when the above error dominates the error log- note that in the normal case probably with fewer users, chat rooms work fine)

How to stop this error ?

2016.03.22 08:15:18 XMPPServlet - XMPPWebSocket deliver java.lang.IllegalStateE$…

2016.03.22 08:15:18 XMPPServlet - XMPPWebSocket deliver java.lang.IllegalStateE$…

2016.03.22 08:15:18 XMPPServlet - XMPPWebSocket deliver java.lang.IllegalStateE$…

2016.03.22 08:15:20 XMPPServlet - XMPPWebSocket deliver java.lang.IllegalStateE$…

2016.03.22 08:15:20

XMPPServlet - XMPPWebSocket deliver java.lang.IllegalStateException: Blocking message pending 10000 for BLOCKING

Which version of Openfire? Which version and vendor of Java?

Hello, Openfire version is 3.10.1 and java is 1.8.0_60 . Any ideas how to solve this? Thank you.

any help on this? I would really appreciate

any help on this ??