Well well well… your new vCenter certificate has messed up your vSphere Replication Appliance and now it won’t connect to the lookup service anymore. I too, was hit by this annoying error, that gives you nothing but a big headache. The VMware KB at first glance tells you to reboot the appliance, but you’ll find yourself rebooting it ad infinitum in the desperate attempts to get your data synchronising between sites again.
The thing is, the wording in the KB is actually correct. However instead of rebooting the appliance as I was trying. You actually need to hard power off the VM completely, wait a couple of minutes, then power on the VM again. This is due to the certificate thumbprint sticking around in the OVF properties of the replication appliance. By powering off and waiting, it appears this value gets cleared somewhere along the line. Once booted up, you’ll find the appliance connects to vCenter without issue. Certainly one of the easier but more confusing ways of fixing a problem. I’d wager that the VMware KB needs to be clearer in explaining this as your run of the mill engineer (i.e me) is just going to assume that a reboot will suffice… which it won’t.
Anyway, hopefully someone out there found this helpful. If you did, then be sure to chuck a comment on this post so that I may get a warm fuzzy feeling. ❤️