[serivo]

I have a strange problem with memcached. When I have commented out all memcached lines in my /opt/zimbra/conf/nginx.conf pop3 authentication works perfectly. But with these lines I have one successfull login and then during about a minute - all logins are failing When I have started memcached with -vv option, I see something like this:
---
<3 server listening
<7 new client connection
<8 new client connection
<8 incr ip:192.0.2.1 1
>8 NOT_FOUND
<8 add ip:192.0.2.1 0 60 1
>8 STORED
<8 incr usr:test@test.example.com 1
>8 NOT_FOUND
<8 add usr:test@test.example.com 0 60 1
>8 STORED
<8 get POP3:test@test.example.com
>8 END
<8 add POP3:test@test.example.com 0 3600 18
>8 STORED
<8 incr ip:192.0.2.1 1
>8 2
<8 incr usr:test@test.example.com 1
>8 2
<8 get POP3:test@test.example.com
>8 sending key POP3:test@test.example.com
>8 END
<8 connection closed.
<7 incr ip:192.0.2.1 1
>7 3
<7 incr usr:test@test.example.com 1
>7 3
<7 get POP3:test@test.example.com
>7 sending key POP3:test@test.example.com
>7 END
<7 connection closed.
---
Zimbra version 5.0.3.
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WBR,
Sergey.