Yes I agree and thought it was originally. Most common reasons for 502 error is server side but also can be network related.
Turns out NOT PF Sense ("probably not PF " == NOT PF) but probably the Ubiquity Gear. I just got out some cables and connect the Mac to physical port and turned off Wifi. Got there without issue.
The DNS, Whois, etc. seems to show different items in that the Registration appears to be domains@bevisible.com with an IP of 35.190.57.191. However, the certificate today looks different than the one from yesterday.
Originally on their website and logged into the site with Chat when tried a link of the page. Got the error. Thus, thought they went down. Now makes me wonder if something is spoofed from UBNT gear.
Thanks for looking! On to UBNT configs. ;-)