When attempting to register the vSphere Replication appliance to the PSC, you may encounter this error:

Error

Server returned 'request expired' less than 0 seconds after request was issued, but it shouldn't have expired for at least 600 seconds.

On the appliance, look in the log file /opt/vmware/hms/logs/hms.log: if you see messages similar to the following, the time of the replication appliance and the PSC may not be in sync.

/opt/vmware/hms/logs/hms.log

2017-01-14 06:57:00.694 ERROR com.vmware.vim.sso.client.impl.SoapBindingImpl [main] (..client.impl.SoapBindingImpl) | SOAP fault javax.xml.ws.soap.SOAPFaultException: The time now Wed Jan 18 12:27:31 MST 2017 does not fall in the request lifetime interval extended with clock tolerance of 600000 ms: [ Sat Jan 14 06:47:00 MST 2017; Sat Jan 14 07:17:00 MST 2017). This might be due to a clock skew problem.

To resolve, make sure the appliance and the PSC have the same date and time. The quickest way to do this, is by setting the time manually, but it is preferrable to configure NTP servers on both appliances.

Note that if the replication appliance has just been deployed, the most likely cause for the clock skew is a wrong time setting on the ESX host running the appliance. In this case, you should correct the time on the ESX host as well (either manually or through NTP servers).