Hi @Aloner. Welcome to GoDaddy Community! For a CNAME, you would need to specify a subdomain. A good example of this is the WWW CNAME. For that, the host is 'WWW' which points to '@'. The @ host cannot be used as the host for this type of record. Sorry for any confusion.
JesseW - GoDaddy | Community Manager | 24/7 support available at x.co/247support | Remember to choose a solution and give kudos.