Cribl.Cloud Workspace Page Shows a Client-Side 404 Behind a Secure Web Gateway

Symptom

When opening a Cribl.Cloud workspace page, the browser displays a 404 or "Workspace not found" page even though:

• The user can sign in to Cribl.Cloud.
• The workspace exists and is active.
• Requests in the browser Network tab return HTTP 200.

The browser console may show errors such as:

• Cross-Origin-Embedder-Policy or Cross-Origin-Resource-Policy blocking errors.
• ERR_BLOCKED_BY_RESPONSE for requests to api.cribl.cloud.

Environment

• Cribl.Cloud workspace access through a secure web gateway, proxy, or TLS-inspecting firewall.
• The proxy can modify response headers for Cribl.Cloud requests.

Resolution

1. Open the affected workspace page in a private/incognito browser window.
2. Open the browser developer tools and select the Console tab.
3. Reproduce the issue and look for COEP, CORP, or ERR_BLOCKED_BY_RESPONSE errors.
4. In the Network tab, verify that the workspace-list request returns HTTP 200 and includes the expected workspace.
5. Ask the network security administrator to bypass proxy inspection or response-header rewriting for Cribl domains. At minimum, include:
   • *.cribl.cloud
   • *.cribl.io
6. If the secure web gateway supports separate controls, disable TLS decryption and security-header injection for the Cribl domains.
7. Clear the browser session or open a new private window, sign in again, and reload the workspace page.

If the issue persists, reproduce it from a network that does not use the proxy. If the workspace loads there, the secure web gateway remains the likely cause.

Cause

The 404 is generated by the Cribl.Cloud user interface when the workspace list is unavailable to browser JavaScript. A secure web gateway can inject or rewrite security headers—for example, Cross-Origin-Embedder-Policy: require-corp and Cross-Origin-Resource-Policy: same-origin—on requests between the Cribl.Cloud management page and its API.

The network transfer can still complete with HTTP 200, but the browser blocks the response from being exposed to JavaScript. The UI then receives no usable workspace list and renders the "Workspace not found" page.

Additional Information

• A 404 rendered in the page does not necessarily indicate an HTTP 404 from the Cribl.Cloud API.
• Inspect the browser console and response headers, not only the Network status code.
• If proxy bypass is not possible, provide Cribl Support with a HAR file and browser console output captured while reproducing the issue.