The primary reason for this error is due to the fact that the `chrome.extension.onRequest` listener is not properly configured. The listener expects a request object with a specific structure, but in your case, you are only passing a callback function.Another possible cause could be related to the m

How do I fix: Check manifest.json file for errors or missing fields?

Step 1: Verify that the `manifest.json` file contains all required fields, including the correct `background` and `content_scripts` sections.Step 2: Check for any syntax errors in the JSON file.Step 3: Test the extension with a simple request to ensure it's working correctly.

Software⏱️ 3 min read📅 2026-06-04

How to Fix: Port error: Could not establish connection. Receiving end does not exist. In Chromiume

Q: How do I fix: 🚀 How to Resolve This Issue Verify and correct the `chrome.extension.onRequest` listener configuration?

Step 1: Check that the request object passed to the listener has the correct structure, including a `req` property with the requested command.Step 2: Make sure that the callback function is properly defined and matches the expected signature.Step 3: Test the listener with a simple request to ensure

Check the port number in your manifest.json file and ensure it is not conflicting with another extension or process.

Quick Answer: Verify that the port number in your manifest.json file is unique and not already in use by another extension or process.

📋 Table of Contents

⚠️ Common Causes
🚀 How to Resolve This Issue
🎯 Final Words

The 'Port error: Could not establish connection. Receiving end does not exist' error in Chromium occurs when the extension is unable to establish a connection with the receiving end.

This issue affects developers who are using Chrome as their browser and have an extension that relies on sending requests to the background script.

⚠️ Common Causes

The primary reason for this error is due to the fact that the `chrome.extension.onRequest` listener is not properly configured. The listener expects a request object with a specific structure, but in your case, you are only passing a callback function.
Another possible cause could be related to the manifest.json file not being correctly formatted or missing required fields.

🚀 How to Resolve This Issue

Verify and correct the `chrome.extension.onRequest` listener configuration

Step 1: Check that the request object passed to the listener has the correct structure, including a `req` property with the requested command.
Step 2: Make sure that the callback function is properly defined and matches the expected signature.
Step 3: Test the listener with a simple request to ensure it's working correctly.

Check manifest.json file for errors or missing fields

Step 1: Verify that the `manifest.json` file contains all required fields, including the correct `background` and `content_scripts` sections.
Step 2: Check for any syntax errors in the JSON file.
Step 3: Test the extension with a simple request to ensure it's working correctly.

🎯 Final Words

To resolve this issue, you need to verify and correct the `chrome.extension.onRequest` listener configuration and check your manifest.json file for errors or missing fields. By following these steps, you should be able to establish a connection with the receiving end and fix the 'Port error: Could not establish connection. Receiving end does not exist' issue.

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