There are many reasons node pinging can fail but one of the most common issues I have found for this is caused by the keystore on the weblogic web instance.
Most organizations will load in there SSL certificates and change the default passwords of the keystore. When this happens you have to modify the integrationGateways.properties file to tell it the keystore file name and path and the password for the keystore.
You can modify the file online in PeopleSoft from the gateway setup page or on the backend system by navigating to the PSIGW applications folder on the weblogic instance.
Look for the lines and update them accordingly:
Save the file and try the ping again. They should now successfully ping.