Failed to send HTTP request or read HTTP response

[d4d]

Hi
I have:
Server A - IBM Cognos 8.4
Server B - IBM Cognos 8.4
Server C - Content Store (Oracle 10g)
All a server IBM Cognos 8.4 are customised on one server Content Store.

When first starting Server-A and second Server-B it's work.
When first starting Server-B and second Server-A. Server-A starting error.

ERROR [       com.cognos.p2plb.model.NodeHospital] Thread-14: Ping of sick dispatcher Server-B:9300/p2pd/servlet/dispatch failed.  Error code = Failed to send HTTP request or read HTTP response