The page displays a weird 403page when I reverse proxy a CLOUDFLARE site, sometimes

[sleepyjoeschool]

What is the name of the domain?

sonolus-milkbun-org.server.sonolus.top → sonolus.milkbun.org

What is the error number?

403

What is the error message?

403 Forbidden Cloudflare

What is the issue you’re encountering

When I tried to reverse proxy a site(https://sonolus.milkbun.org/), everything looks fine, the page looks working. However, in my Service status page, it says the page down with a code 403, I tried to access and it says “403Forbiddn cloudflare”. Its a simple page very similar with nginx 403 page.

[ikmal]

Hello,
If you’re seeing a 403 error without Cloudflare branding, this is always returned directly from the origin web server, not Cloudflare, and is generally related to permission rules on your server.

The top reasons for this error are:

1. Permission rules you have set or an error in the .htaccess rules you have set
2. Mod_security rules.
3. IP Deny rules

Since Cloudflare can not access your server directly, please contact your hosting provider for assistance with resolving 403 errors and fixing rules. You should make sure that Cloudflare’s IPs aren’t being blocked.

There are some instances where Cloudflare will serve a branded 403 error page. Please review the below knowledge base article and community tip on resolving 403 Errors:

4xx Client Error

[Community Tips- Fixing Error 403 Forbidden] (Community Tip - Fixing Error 403 Forbidden)

[sleepyjoeschool]

I dont think so, because the error only happened very few times per day, likely 2-3 times and only kept 1-6 minute each time it happened.

[sleepyjoeschool]

But I already let the server owner to check the WAF logs in their CLOUDFLARE dashboard.