After upgrading our master to CloudBees 184.108.40.206.1, which picked up a back-ported SECURITY-534 fix, I was unable to view the server list on the Gerrit Trigger status page. The table simply read "Data Error." and the /gerrit-trigger/serverStatuses call returns a 404. The servers themselves seemed functional according to the logs. Also in the logs:
Adding the above to the whitelist fixed the issue.