idpf epub validator seems down

Looks like http://validator.idpf.org/ is down (don't know from when).


I was reading through this doc today 
https://w3c.github.io/epub-tests/contributing

when I was going through Step 9 "Run the EPUB through the onlineEPUB 
Validator <http://validator.idpf.org/>or theEPUBCheck 
<https://www.w3.org/publishing/epubcheck/>command-line tool to ensure 
you didn’t make any silly mistakes. Fix if you did."

I tried to open the EPUB Validator but seems could not open anymore (or 
maybe taking too long).


Thanks

-- 
Zheng Xu

Chief Executive Officer
Gardenia Corp
https://gardenia-corp.com/