DocumentationExperience Cloud KCS

Dispatcher filter rules blocking requests causing 404 or blocked errors

Last update: June 27, 2026

Requests that should reach the application are sometimes blocked by dispatcher filter rules, resulting in 404 responsesor blocked request errors. To resolve the issue, update filter rules and redeploy the configuration.

Description description

Environment

  • Adobe Experience Manager as a Cloud Service (AEMaaCS)
  • On-premise deployments
  • Dispatcher-based caching and filtering setups

Issue/Symptoms

  • HTTP 404 responses for valid resources
  • Requests marked as blocked in dispatcher logs
  • Servlet endpoints return errors in one environment but work in another
  • Static assets outside standard paths are not accessible
  • Asset renditions fail to load
  • Unexpected request failures despite the resource existing

Root cause

Dispatcher enforces an allowlist model where a default deny rule blocks all traffic unless explicitly allowed. Missing allow rules, incorrect rule ordering, malformed configurations, or improper pattern matching can prevent valid requests from passing. Cached responses may hide the issue, making it harder to identify.

How to confirm

  • Reproduce the issue and capture the full request URL
  • Check dispatcher logs for blocked request entries
  • Identify the specific filter rule number blocking the request
  • Review filter configuration files to verify whether the request path is allowed

Resolution resolution

To resolve the issue:

  1. Identify the exact request URL that fails, including parameters and selectors.
  2. Check dispatcher logs to find blocked entries and note the rule number.
  3. Review filter configuration files to locate deny and allow rules.
  4. Determine whether the request path should be allowed.
  5. Add or correct an explicit allow rule that matches the request path and method.
  6. Ensure the rule is ordered correctly so it is applied after the deny-all rule.
  7. Redeploy or reload the dispatcher configuration to apply changes.
  8. Validate that the request succeeds and no unintended access is introduced.
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