Before i can add by freenom
but now i change account , my domain can’t add to new account
That domain is registered under a TLD which is governed by the Freenom registry. Freenom currently experiences issues with their Whois service which prevents such domains from being added to Cloudflare. Freenom needs to fix that on their side. Unfortunately there is no ETA known for that.
It probably is best to register a proper domain instead. They already go for less than $10 a year.
but before can
Of course it was. But not now.