api.esoui.com is the same server that serves this forum/site so are you getting any 502's browsing the site?
Sounds like our CDN cloudlfare may be having issues with your geolocation? If that is the full error page then its likely an issue with the cloudflare node that is closest to you. Usually there is a transaction id on errors and since there is a lack of that it looks like an issue with their internal network.
Can you visit
https://api.esoui.com/cdn-cgi/trace and let me know what 'colo' you are connecting to?