Error 525 while pointing to Google sites

I have setup several CNAMEs and their are working fine. That includes one to my main website which is a simple Google Sites (GS) site (
Now I created another website on GS and used the same steps to have a sub domain pointing to it (, and that one raises error 525.
SSL/TLS encryption mode is Full, both CNAMEs are proxied.
I correctly set the parameters in GS, I check twice.
Any clue ?

Latst day it was an outage of Cloudflare for the error 525 . You can google it.

issue disappear, not sure how. I disabled the proxy and waited a bit.