Website offline

Hello,
I have a problem with my site. When I activate the Cloudflare feature, the site works for a short period, then it does not work and becomes out of work? I do not know… What is the reason for this, I had to stop the service temporarily… Is there an error in the setup or from the hosting?

Isn’t there any error code?

Make sure the site works properly before adding it to Cloudflare.

Pausing Cloudflare and checking would be better.