I assume you mean forums.virtualbox.org?
I'm on Chrome on Windows 10 and do not see this error. Google the error & troubleshoot on your end, I doubt it's the forum servers doing this.
Could be a bug in Mac Chrome or a bug here. Not enough info to make a determination, was just curious if anyone else was experiencing it. I did report it.
I don't see the problem using "Blue Moon" (a Firefox fork), nor with Microsoft's Edge browser. On two separate machines (home and work) that I use constantly.
I think you can be pretty sure that your problem is local. Do you have a slow internet connection?