From Reddit user rebbsitor, "After reading about RMS having his laptop stolen, I clicked the link to donate.fsf.org. I'm at work at the moment, and our IT department uses Microsoft Threat Management Gateway to prevent access to certain types of sites. If you're not familiar with this software, it's essentially a proxy that assigns websites to categories and can be configured to block any set of categories. This is the response when connecting to donate.fsf.org:
Network Access Message: Access Denied
[Explanation on who to contact in our company for more info redacted]
The page you are trying to browse to is categorized as "Gambling"