A client found this issue after installing the PAM SC endpoint on several Linux machine in one specific environment All machines were running RHEL 7.8 and all used the latest supported version of PAMSC. When the PAM SC Endpoint was started the password verify and password rotations would both fail. After unloading the endpoint service both resumed working fine.
Sample error from the tomcat log on the PAM server
We found a network timeout was encounter specific to a failed DNS lookup of the PAM Appliance from its IP. Since the PAM SC endpoint required the hostname this extra time used in name resolution caused a timeout in the process that runs the verification process. The key indicator to the timeout was the error in the tomcat.log " channel is not opened."
PAM SC Release : 14.1
Component : PAM SERVER CONTROL ENDPOINT WINDOWS
A temporary fix was used by simply adding the IP and hostaname to the /etc/hosts file but the full resolve was to modify the /etc/resolv.conf and add the appropriate NS server into the list of name servers. After resolving this issue all password updates were also faster than previous with or without the PAM SC endpoint loaded