How to fix “ERR_PROXY_CERTIFICATE_INVALID”. Step-by-Step Guide

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How to fix “ERR_PROXY_CERTIFICATE_INVALID”. Step-by-Step Guide






How to Fix "ERR_PROXY_CERTIFICATE_INVALID" Error

Learn how to resolve the "ERR_PROXY_CERTIFICATE_INVALID" error with simple troubleshooting steps such as checking system time, clearing browser cache, updating Chrome, examining antivirus settings, and managing browser extensions. Ensure your SSL connections work smoothly by addressing potential conflicts or misconfigurations. For HTTP Toolkit users, specific fixes like checking port usage and reinstalling the software are also covered.

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Key Takeaways: Resolving “ERR_PROXY_CERTIFICATE_INVALID” Error

Step Summary
Check System Clock Ensure your device’s time and date are accurate. Misaligned settings cause SSL issues.
Clear Cache and Browsing Data Clear your browser’s cache to eliminate old or corrupted SSL certificates.
Update Chrome Browser Use the latest Chrome version to avoid SSL compatibility issues.
Check Antivirus/Firewall Firewall and antivirus settings should allow SSL connections.
Disable Browser Extensions Temporarily disable extensions to rule out any interference with SSL.
Check Website URL Ensure the website URL matches the SSL certificate details to avoid trust issues.
Proceed (Cautiously) Only proceed past certificate warnings if you are sure the website is trustworthy.
Clear SSL State in Chrome Clear cached SSL certificates that may be conflicting.
Specific to HTTP Toolkit Check port usage, reinstall HTTP Toolkit, or manually configure Chrome with trusted certificates.

Now, let’s delve into the expert-level step-by-step guide to resolve the “ERR_PROXY_CERTIFICATE_INVALID” error.

Step-by-Step Guide to Fixing “ERR_PROXY_CERTIFICATE_INVALID” Error

1. Check if Your System’s Clock is Accurate

The system clock plays a critical role in SSL certificate validation. A mismatch in your system’s time and the certificate’s issuance or expiration date often triggers the “ERR_PROXY_CERTIFICATE_INVALID” error. This small issue can step out from the simplest situations, like the clock running out of sync after being manually altered or not updating correctly.

Solution:

  • On Windows:
    Go to Settings > Time & Language > Date & Time and toggle on the “Set Time Automatically.”

  • On Mac:
    Navigate to System Preferences > Date & Time, and ensure that “Set date and time automatically” is checked.

Pro Tip: After syncing time, restart your browser to see if the issue persists. It’s surprising how often this quick fix works, especially for SSL certificate-related problems.

2. Clear Browser Cache and Browsing Data

Browsers store cached versions of SSL certificates from sites you previously visited. If these stored versions become outdated or corrupted, it can cause SSL errors. Clearing this data eliminates potential clashes between old and fresh certificates.

Solution:

  • For Chrome:
    1. Click on the three dots in the upper right corner of the browser.
    2. Go to More Tools > Clear browsing data.
    3. Check the boxes for Cached images and files and Cookies and other site data.
    4. Click Clear data.

This removes any corrupted SSL-related data that could be causing the error.

3. Update Your Chrome Browser

Chrome regularly receives updates that patch known vulnerabilities, including SSL certificate-related improvements. Running an older version of Chrome may cause misinterpretation of otherwise valid certificates, leading to errors like “ERR_PROXY_CERTIFICATE_INVALID.”

Solution:

  • Windows/Mac:
    1. Click the three dots at the top-right corner.
    2. Go to Help > About Google Chrome.
    3. If there’s an update, it will automatically install. Restart your browser afterward.

4. Examine Your Antivirus and Firewall Settings

Some antivirus and firewall systems provide an SSL scanning or deep packet inspection feature, which can intervene with SSL certificate validation.

Solution:

  • Temporarily disable SSL or encrypted connection scanning in your antivirus.
    For example, in Avast:
    1. Open Avast.
    2. Go to Settings > Component > Web Shield.
    3. Uncheck Enable HTTPS Scanning.

If after disabling your antivirus the error disappears, you have identified the root cause. Consider using tools like Malwarebytes for secure malware scanning or MiniTool ShadowMaker to back up your system and ensure your data stays safe while troubleshooting.

5. Disable Browser Extensions

Some third-party browser extensions, especially ones related to content filtering or proxy management, can interfere with SSL certificate checks. Popular extensions like VPNs and content blockers may cause unwanted interruptions.

Solution:

  1. Go to chrome://extensions/ in the Chrome address bar.
  2. Turn off all extensions and restart your browser.
  3. Try loading the problematic site again – if the error is gone, re-enable extensions one by one to find the culprit.

6. Ensure the Website URL Matches the SSL Certificate

If you’re visiting a website and see this error, check if the URL you’re entering exactly matches the domain the site’s SSL certificate is issued for. Even a small discrepancy between “www.example.com” and “example.com” can trigger certificate suspicions.

Solution:

  1. Confirm that the website address is correct.
  2. Look for typos, extra “s” in “https,” or misspelled domain names.

7. Proceed Anyway – But Only if You’re Confident

When faced with a suspicious or self-signed SSL certificate, Chrome offers the “Proceed Anyway” button. This bypasses the security check, but only proceed if you’re absolutely sure that the site is trustworthy. DO NOT ignore such warnings on sensitive websites like online banking or social media.

Solution:

  1. Click Advanced below the SSL warning.
  2. Select Proceed to site (unsafe).

Use extreme caution and only do this for known, trusted websites.

8. Clear SSL State in Chrome

Stored SSL certificates can sometimes create conflicts if they become outdated. Clearing the SSL state in Chrome resets the saved certificates without removing cache or browsing data.

Solution:

  1. Open Chrome.
  2. Go to Settings > Advanced > Privacy and Security > Clear SSL State.
  3. Restart your browser and try again.

Additional Steps Specific to HTTP Toolkit Users

Some users experience this error specifically while using HTTP Toolkit, and the following steps will help resolve it.

1. Check Port Usage

HTTP Toolkit uses specific ports that should be free, such as 45456 and 45457. If these ports are occupied, HTTP Toolkit may fail to start properly.

Solution:

Check your system’s active ports and terminate any process utilizing these ports. You can also kill the background httptoolkit-server node process manually.

2. Reinstall HTTP Toolkit

Sometimes the local installation of HTTP Toolkit can become corrupted.

Solution:

Uninstall HTTP Toolkit and reinstall the latest version. This often fixes certificate issues.

3. Manually Configure Chrome to Trust All Certificates

You may need to manually start Chrome with a configuration that trusts all necessary certificates to avoid this error.

Command:

For Windows users, open the command window and run:

chrome.exe --ignore-certificate-errors --user-data-dir="C:\Users\$YOURUSERNAME\AppData\Local\httptoolkit\Config\chrome" --proxy-server=127.0.0.1:8000 --proxy-bypass-list="<-loopback>;https://localhost:8000" --disable-restore-session-state --no-default-browser-check --disable-popup-blocking --disable-translate --start-maximized --disable-default-apps --disable-sync --enable-fixed-layout --no-first-run --noerrdialogs --flag-switches-begin --flag-switches-end http://amiusing.httptoolkit.tech

Make sure you replace $YOURUSERNAME with your actual Windows username.

FAQ About “ERR_PROXY_CERTIFICATE_INVALID”

1. Why does my browser show “ERR_PROXY_CERTIFICATE_INVALID”?

  • This error appears due to mismatched SSL certificates, wrong domain names, or corrupted cache in your browser.

2. Is it safe to proceed when I see this SSL warning?

  • Only proceed if you are completely sure about the legitimacy of the website. Avoid proceeding on financial websites or email providers.

3. Will clearing SSL State in Chrome delete my browsing history?

  • No, clearing SSL state will not delete your browsing history or any stored site data. It only deletes cached SSL certificates.

4. How can I prevent SSL certificate errors in the future?

  • Keep your browser and system up to date, configure firewall settings properly, and ensure that your system clock is always accurate.

5. Why are SSL certificates important?

  • SSL certificates establish a secure connection between your browser and the website, encrypting any data transferred. This prevents man-in-the-middle attacks and protects sensitive information.
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