In CA Access Gateway (SPS) r12.5x, the parameter
http_connection_stalecheck should be set to "true".
CA Access Gateway (SPS) r12.52 SP1 has a below definition by default
in the Proxy Service section of server.conf.
http_connection_stalecheck="true"
This change was introduced so that the setting may prevent SPS from
unexpected I/O error in the connection between SPS and backend
servers (1).
In earlier version such as r12.51, the default value was "false". It
is recommended that it should be changed to "true".
(1)
Configure the Proxy Service Settings Manually
http_connection_stalecheck
Specifies if a stale connection check must be performed. If you set
the value to true, a stale connection check is performed before each
request execution. If you set the value to false, an I/O error may
appear when you execute a request over a connection that is closed at
the backend web server.
https://techdocs.broadcom.com/us/en/symantec-security-software/identity-security/siteminder/12-52-01/configuring/ca-siteminder-sps-configuration/configure-the-proxy-service-settings-manually.html