I can post on meta with no issue. But for some odd reason I am not seeing the full-blown Stack Overflow site. It appears the CSS is missing from most of it.
When I try to hit the CDN at this link, this is what I get:
The webpage at cdn.sstatic.net/stackoverflow/all.css?v=8a7874f4f2dd might be temporarily down or it may have moved permanently to a new web address