Issue

When saving a custom schema in Panther, I receive a 403 error even though the Test Schema validation completes successfully and I have admin permissions. Why does this happen?

Resolution

This issue is usually triggered by using string text such as angle-bracket generic type notation array<object>, array<string>, or map<string, object> within a schema's description field. To resolve this, remove or rephrase these parts from the description field.

Cause

This is caused by a WAF (Web Application Firewall) security rule that blocks requests containing certain HTML-like syntax strings in the request body (the Test Schema step is a read-only operation that doesn't trigger the WAF).