Troubleshoot network traffic issues

G Suite Sync for Microsoft Outlook

If you're having network-connectivity issues with G Suite Sync for Microsoft® Outlook® (GSSMO), here are some steps that can help you fix the problem.

Fix connectivity issues

Step 1: Open connectivity ports
  • Open port 443 for Outlook.exe and ProfileEditor.exe. Next, reinstall GSSMO from its download page to ensure the installation files download correctly. Our synchronization tools communicate mostly on port 443 so this will resolve many network issues.
  • Open port 80 for downloading the Certificate Revocation List (CRL).
  • Open a Windows firewall port to allow Outlook to communicate with Google's servers. Consult your Microsoft documentation for instructions on how to do this. 
Step 2: Whitelist URLs

You should whitelist the following URLs:

URL Purpose
Authentication Calendar
Certificate Revocation Lists Contacts Global Address Book
Mail Notes Tasks


Note: If you're using a Windows parental control system, you might need to whitelist additional URLs. See your Microsoft documentation for further information.

Review how to find Google IP address ranges. Any one of these IP addresses can be used by GSSMO.

Step 3: Check if you're using a proxy

Authenticated proxies are not supported by GSSMO. To see if you have a proxy:

  1. Close all Internet Explorer® windows.
  2. Open a new Internet Explorer window.
  3. Go to
  4. If you're prompted for proxy authentication, contact your network administrator for help. 

Google Cloud Support is unable to provide support for connection issues when a proxy is in place. 

Step 4: Consult the log files

Additional network problems are logged in GSSMO's trace files. Use the GSSMO Log Analyzer to quickly analyze your trace logs.

Important: Our support team is happy to provide these guidelines for setting up your network to work with GSSMO. However, we can't assist with your network configuration. For help with that, contact your local network administrator.

Was this helpful?
How can we improve it?