Metabox License Key not working on new install

I'm working on a new site, and we're trying to add the same license key I've been using for a long time. I purchased the lifetime bundle. For some reason, the key isn't working. It says when we try to verify it that it can't connect to the meta box servers. Currently, the site is hosted locally and we are behind a proxy. I'm not sure if that would be causing the issue, or if it is something else. We're using the latest version of all the plugins.

Thanks.