Error 'mydomain.my.salesforce.com refused to connect' in Salesforce Gmail Integration Chrome Extension

Step 1: Clear the Gmail Integration Extension Cache

Clearing the Gmail Integration extension cache improves performance by removing stale data. Follow the steps in the Salesforce Help article: Clear the Cache of Gmail Integration Extension.

Step 2: Clear Chrome Browser Cache and Cookies

Browsers retain cookies and cached data over time, which can cause issues with website logins and page rendering. Follow the Google Help article to clear cache and cookies in Chrome.

Step 3: Add Salesforce as a Trusted Site in Chrome

Adding Salesforce domains to Chrome's trusted sites list allows the extension to communicate properly.

1. Open Chrome settings.
2. Navigate to Site Settings.
3. Under Permissions, open Cookies and site data.
4. In the Allow section, click Add and enter the following trusted sites one at a time:
   1. [*.]content.force.com
   2. [*.]salesforce.com
   3. [*.]Salesforceiq.com

Step 4: Remove the Gmail Connection from Third-Party Account Links

Revoking the existing Google connection can clear stale authorization tokens.

1. In Salesforce, go to Setup > Users and select the affected user.
2. Navigate to Third-Party Account Links.
3. Click Revoke for Google.

Note: Check whether any legacy account connections (such as Gmail Integration with Inbox) are still present and revoke or delete those as well.

Step 5: Verify Secure Connection Settings in Salesforce Session Settings

The following options must be enabled in Salesforce Session Settings under Require secure connections:

• Require secure connections (HTTPS)
• Require secure connections (HTTPS) for all third-party domains

These options should be checked by default after the Summer '21 release.

Step 6: Reinstall the Salesforce Gmail Integration Chrome Extension

If none of the above steps resolve the issue, uninstall and reinstall the Salesforce Gmail Integration Chrome extension from the Chrome Web Store.