I purchased a new licence for Zimbra and uploaded it to the server.

When I go to active, the message: Licence error encountered.

The detail in the message is:
Proxy Error
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request

I ordered the "Starter Edition" so I don't have a support login that I can use to manually active the request.
How do I resolve this?