Not sure. Where the company I work for operates they have some very weird proxy setup (not my company’s rule but the host). Largely it seems only effective at blocking legitimate content for nonsense reasons. My own site gets blocked on occasion, though I’ve lazily let the cert expire. That reminds me....

Anyway I wouldn’t worry too much. It’s likely just stodgy corporate environments that put those kinds of controls in place.

Good to know, thanks