Software⏱️ 2 min read📅 2026-06-03

How to Fix: CUSTOM_ELEMENTS_SCHEMA added to NgModule.schemas still showing Error

Learn how to fix: CUSTOM_ELEMENTS_SCHEMA added to NgModule.schemas still showing Error.

Quick Answer: Try checking your system settings or restarting.

📋 Table of Contents

  1. 🛑 Root Causes of the Error
  2. ✅ Best Solutions to Fix It
  3. 💡 Conclusion

The error 'cl-header' is not a known element

🛑 Root Causes of the Error

  • Angular 2 rc6 has changed its schema, and custom elements are not automatically registered.

✅ Best Solutions to Fix It

Adding CUSTOM_ELEMENTS_SCHEMA to NgModule.schemas

  1. Step 1: Import the CUSTOM_ELEMENTS_SCHEMA in your main application module (AppModule).
  2. Step 2: Add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of your main application module.
  3. Step 3: This will register custom elements and prevent the error from occurring.

Using Web Components with Angular

  1. Step 1: Check if you are using Web Components in your project.
  2. Step 2: If yes, then ensure that they are correctly registered with the Angular framework.

💡 Conclusion

To resolve the issue, add CUSTOM_ELEMENTS_SCHEMA to NgModule.schemas in your main application module. This will register custom elements and prevent the error from occurring.

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