I have been seeing this error intermittently since some time just after 09:55 PDT on 7/17:
504 Gateway Time-out
cloudflare-nginx
It is affecting access to the web interface and API stats.
Could this be collateral damage from the Network Solutions DDOS?
Looks like this finally cleared up around 14:20 today (GMT-7), and had been happening for me since my earlier post.
I haven't been experiencing this issue at all in the last week, with the exception of periods where the site was under direct attack, or when a large script runs (~4 times per hour), though that's normally just a slow load, and doesn't generate an error page before the script is done running.
through AT&T (both residential and business circuits). Whatever it was, it appears to have cleared up and has been stable since yesterday afternoon.