Hey there, @David_Gourdet 
Thanks for reaching out, and welcome to the Netlify Forums!
So this error essentially means “we tried to make a wildcard certificate since you have DNS hosting enabled. However, the DNS record we made was not found by lets encrypt, so provisioning failed.” What this means is that you have an inactive DNS zone that you will need to disable before we can extend the certificate to your site.
You can follow this support guide to walk through deleting inactive DNS:
Let me know if this gets you on the right path!