After you move your website to a new provider, Cloudflare may send you an email titled ‘Action required: restore nameservers’. If the move was intentional, you do not need to do anything.
Why this happens. Cloudflare has detected that your domain’s nameservers no longer point at Cloudflare. Cloudflare’s copy of your DNS zone is no longer in use, and Cloudflare removes it automatically after about a week. Your live site and email keep working from the new nameservers.
When to follow the instructions. Follow the ‘restore’ instructions in the email only if you moved the nameservers by mistake and still want Cloudflare to serve your domain.