SSO failing with Error: Signature is invalid

Hello,
I'm trying to configure an SSO Login with SAML. my Idp (Cloudflare Access) provides me with a metadata xml that I copy to OVH SSO. I'm already using Cloudflare to login with AWS and many other services. I can't figure out why with OVH I'm getting this signing error, propably a bad description to another problem.
Anyone has SSO working OVH ?
Update: I tried to configure using Google Workspace but I get the same error
Suggestion for OVH: Please provide a way to redirect to login page with prefilled account id number
!37|683x432
!28|435x500

Any Help from OVH ?
DO you even have support for OVH Cloud ?