w3c Validator returning 503 Service Unavailable error when testing sites

Dear w3c validator list,
I am a regular user of the w3c validator service over several years of
teaching students who build semester project websites. We were using the
validator at https://validator.w3.org/ with no problems at least a week
ago. However, yesterday and today, when I test any website URLs, I am
receiving 503 Service Unavailable errors. Example site addresses I have
tested include https://newtfire.org/courses/textEncoding/teSyll.html and
https://dxh405.github.io/hughes_project/ .

I have not seen any recent reports on the mailing list of the 503 error, so
I am hoping this is something quite temporary!

Thanks for taking a look!

Elisa Beshero-Bondar | eeb4@psu.edu
Program Chair of Digital Media, Arts, and Technology | Professor of Digital
Humanities |  Director of the Digital Humanities Lab at Penn State Erie,
The Behrend College
Development site: https://newtfire.org

NOTE: Whenever possible, give the address of the document you were checking.