Error installing Octopus Tentacle - 403 Forbidden

Hi All,
I’m having an issue scripting the installation of the Octopus tentacle to one server whereas an identical installation to some other servers worked without issues. The command I’m issuing is as follows:

“C:\Program Files (x86)\Octopus Tentacle\Agent\tentacle.exe” register-with --server=http://octopus -environment= --apikey= --force

Error Message: System.Net.WebException: The remote server returned an error: (403) Forbidden.

As I said, other installations have been fine so I doubt it is with the command or an incorrect api key so any hints on where else to check would be appreciated. I noticed the registry key is not deleted, however I also removed this key prior to a fresh installation of the tentacle just to make sure. The Octopus version we are using is


You could try using Fiddler to see details of the error, and check the event log on the Octopus server. Is there a proxy server between the machine and the Octopus server that might be returning the 403? What happens if you type http://octopus into a web browser on the Tentacle server?