The Log sink has been set to push audit logs to a syslog server. The hostname of the Syslog server has been used in the configuration as stated in the document:
If there is a change in the IP address of the Syslog server, the Gateway fails to pick up the new address.
The gateway is working as designed. The gateway does not check for IP address change every time it sends out a syslog. The gateway service has to be restarted for the DNS to be checked.