Using vSphere Data Protection (VDP), I have seen the following error a few times and it has appeared in forums so I thought it would make sense to post a short article on it.

“The most recent request has been rejected by the server. The most common cause for this error is that the times on the VDP appliance and your SSO server are not in sync.”

That is an example of a well-written error message – thank you, VDP developers. As the error suggests, it is likely an issue of time difference between the VDP appliance and the VMware vSphere Single Sign-On (SSO) server it is linked to. To resolve the issue, make sure the vSphere host that is running the VDP appliance has its NTP client configured properly and running. In the vSphere Web Client, this is done by selecting a host, clicking the Manage tab, and then clicking Time Configuration.

Do the same for the host running the SSO server using the same NTP server, of course. If you are running the SSO server on a Windows server (virtual or physical), make sure Windows is configured with the proper time zone for its location, as well. Last, but not least, make sure the latest version of VMware Tools is installed in your virtual machines. Most virtual appliances, including the vCenter Server and VDP appliance, come with VMware Tools already installed.

In a few situations, I have seen the need to restart VMware Tools in the vCenter Server and VDP virtual appliances to force a time sync with the vSphere host they are running on. This can be accomplished by running the following commands at the command line of each appliance:

(vCenter Server virtual appliance)# service vmware-tools-services restart

(VDP virtual appliance)# service vmware-tools restart

In a VMware virtualized environment and in just about any environment, for that matter, it is best practice to make sure…
1. DNS name resolution is configured and working properly – forward and reverse lookup, long name and short name.
2. All hosts are configured to use an accurate and reliable source of time – preferably, the same source.