We're getting errors when trying to update the plugin and when trying to activate a license. I checked the Installer Support logs and we're seeing the following error:
Your site can't communicate with hidden link. Code 403.
I've looked through the troubleshooting steps and contacted Pantheon (the site host) about whitelisting the URLs and they told me that they do not block any URLs. This error is also occurring on other sites we have hosted on their platform.
Looking at the Installer Support logs the error seems to have started happening around August 23rd.