Error encountered while adding CNAME record

[JxstErg1]

Hi and welcome to the forum! You can only use free subdomains on free hosting, exceptionally on Premium Hosting if you migrate your website to them, then nowhere else. You can consider getting your own domain if you want to point it anywhere else; here are some places where you can get one for free:

Where do I get free domains?

You can try using EU.org or PP.UA (the latter one if you have a credit card even with a few cents on it and a phone number to use for verification, though the credit card is used only once for verification and then what’s free will remain free) as a valid alternative to Freenom (and Dot TK because Dot TK and Freenom are the same) that also supports Cloudflare and other things that Freenom with its domains supported.