CName Record returns 521 error

Hello there,

I have an API Gateway on Oracle Cloud Infrastructure. There is a simple Apache server behind it on a Linux VM. I am able to access directly through API Gateway’s end point FQDN.

However I am unable to access the API Gateway’s endpoint through a CNAME Record on my Cloudflare DNS.

Does someone know how may I fix it?

A similar set up (same Linux VM and Apache combo) is working fine using another CNAME record on Cloudflare to a WAF Endpoint on Oracle Cloud Infrastructure.


A 521 error happens when Cloudflare is unable to make a TCP connection to your origin server. Review the suggestions in this Community Tip for Quick Fix Ideas.

thanks @cscharff.

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