WAF POST rejecting 8k payload

What is the name of the domain?

infinyon.cloud

What is the issue you’re encountering

WAF is rejecting POST requesting exceed 8k payload

What steps have you taken to resolve the issue?

Send payload with less than 8k which succeed.
When payload is greater than 8k, it rejects

Was the site working with SSL prior to adding it to Cloudflare?

Yes

What is the current SSL/TLS setting?

Full

What are the steps to reproduce the issue?

create JSON body greater than 8k.