I see what’s going on. Using a dig tool on “www.slavisamediabox.42web.io” reveals a CNAME record pointing to a subdomain of “.googlehosted.com”. This means that OP is still trying to use DNS verification to add their domain to the Google Search Console, which means they still haven’t followed the directions they were given earlier.
It’s more than possible to add a free subdomain to GSC, as long as you follow the directions and do it properly.