If there are not sufficient signalling paths defined to provide at least one inbound and one outbound path between each of the systems in the sysplex, XCF on the initializing system issues message IXC453I to indicate that signalling path connectivity could not be established.

The operator is then prompted for a different COUPLExx parmlib member.

Check also for message IXC451I on other systems in the sysplex. This message indicates incorrect signalling path definitions that can result in message IXC453I.