swi-prolog.org services run on a pair of machines, one at VNU in Amsterdam and one at the Oregon State University Open Source Lab, coordinated by the Fastly CDN (thanks to all those folks, who donate their services).
Services that must persist changes (wiki on the website, SWISH, etc) run from the VNU server.
That server is currently down. Jan is in China, and until we can raise him and get him to restart, all eu.swi-prolog.org services may remain down.