I checked your accounts, but the domain detigres.ga is currently not assigned to any account on InfinityFree. Can you please make sure that your domain name is assigned to a hosting account here?
The domain still doesn’t seem to be in use here. It’s currently pointing to atspace.me nameservers. If you want to setup CNAME records on our hosting, you’ll have to change that to ns1.epizy.com and ns2.epizy.com.
And if you get this error while trying to add the CNAME record to atspace.me’s nameservers, please contact them for help on how to use their DNS settings. I don’t know how those work or why they don’t accept your input.