After you buy a domain name, you must file it through ICP before the domain name registrar dares to open a domain name resolution service for you. In other words, you have registered a domain name. If there is no ICP filing, you have the custody right of the domain name, but you have no right to use the domain name.
Now ICP filing is stricter year by year, which expresses the determination and strength of the competent authorities to strengthen Internet monitoring.