As @arun mentioned above, if you want to change your domain’s nameservers to Hostgator, go to your registrar – where you purchased the domain from – to make the change. Cloudflare does not control this.
Note that doing this will disconnect your site from Cloudflare completely, and your can no longer benefit from any of the security and performance services Cloudflare offers.
In most cases you don’t need to change nameservers at all. You can keep the Cloudflare nameservers and point DNS records to your Hostgator server’s IP address (you can find this in your Hostgator cPanel).
The site www.smartsuriname.sr does give 404 error message and hostgator told me it is not pointing to their dns servers because they also try to have the SSL certificate fixed, but still have the issue, They already pointed out the dns records,
I see that both the root domain and the www subdomain point to a specific IP address. Can you reach out to HostGator and ask if that’s all that you need to do for the SSL to be provisioned at their end? It is not entirely necessary to change name servers from Cloudflare to HostGator, as @GeorgeAppiah mentioned above.