[Plugin: Jetpack by WordPress.com] Jetpack could not contact WordPress.com

I am trying to use the Jetpack plugin for a self-hosted installation at:

http://gwprovide.org

When trying to connect to Jetpack, I receive the following error:

Jetpack could not contact WordPress.com: register_http_request_failed. This usually means something is incorrectly configured on your web host. Failed to connect to 76.74.254.123: Permission denied

I am a web developer with multiple clients on the same server. This is the only account on the server that is unable to connect. Can anyone shed any light on where I might try next to fix this issue?

http://wordpress.org/extend/plugins/jetpack/