CAS 4.1.4 - Memcache- RuntimeException: Exception waiting for value

[Ognisty Sztorm]

Hi !

I have problem with cas.

My environment is:

server a: 

      

        cas app, tomcat 7, memcache ,centos 7 64 bit, openjdk 8

server b: 

         memcache ,centos 7 64 bit, openjdk 8, postgres 9.4 

Cas behaves strange in my app. When I use my automatic tests(first ask for 

a token and then for two hours every minute I ask cas 'is this token valid') 

I see that after a few requests from time to time I recieve "token expired'  answer.

It looks like this:

request 23 ok

request 24 token expired

request 25 ok

request 26 ok

...

request 43 token expired.

In my logs I saw :

2016-07-01 16:26:07,047 ERROR [org.jasig.cas.ticket.registry.MemCacheTicketRegistry] - <Failed fetching [TGT-**********************************************MfNAaFrbPN-devas106b-cas.arkena.com, java.lang.RuntimeException: Exception waiting for value] >

Could some one explain me what this error means? I tried to find info in internet but I failed.

Could any one give any hint how to fix this?

(I tried: change GC and timeouts, use open jdk7, use oracle jdk7, use only one memcache node...nothing helps )

Thanks in advance!