Server error with Salesforce Outlook Add-In

Question

We are currently experiencing a server error with one of our Salesforce users in the Salesforce Add-In for Outlook (https://appsource.microsoft.com/de-at/product/office/WA104379334?tab=Overview), which we are unable to resolve.

The add-in can be installed and the user can log in. Data from Salesforce is then displayed, but no logging can be performed as a server error is displayed. The error code is empty.

The user uses the same email address in his mailbox and for his Salesforce account.
He has linked several email addresses to his Outlook program. Removing the other email addresses from his outlook program does not resolve the problem.

Any idea how we can fix this issue?

Answer 1

Dear customer,

Thank you for posting in Microsoft Community.

I understand you are experiencing a server error with the Salesforce Outlook Add-In where the user can log in and see Salesforce data, but cannot log emails due to a generic server error. This error typically indicates a problem with the add-in’s connection to the Exchange server, which is essential for logging emails. Here are a few steps you can try to resolve this:

1. Verify Exchange Web Services (EWS) Connectivity and Permissions

• The Salesforce Outlook Add-In relies on Exchange Web Services (EWS) to interact with the mailbox.
• As an Exchange or Microsoft 365 admin, confirm that EWS is enabled for the affected user:
  • Go to Exchange Admin Center (EAC) > Recipients > Mailboxes.
  • Select the user’s mailbox and check Mailbox features > Connectivity to ensure EWS is enabled.
• Check for any EWS Application Access Policies that might block the add-in:
  • Use PowerShell commands like 
    Get-OrganizationConfig -EwsApplicationAccessPolicy and Get-CasMailbox -Identity "User" | Select EwsApplicationAccessPolicy .
  • Ensure the Salesforce add-in’s app ID or user agent is allowed.

2. Reinstall the Add-In and Clear Cache

• Remove the Salesforce add-in from Outlook:
  • In Outlook desktop, go to File > Manage Add-ins or via Outlook Web Access (OWA) under Settings > Manage add-ins.
• Clear Outlook and browser cache:
  • Close Outlook completely.
  • Clear browser cache and cookies (since add-ins run as web apps inside Outlook).
  • For Outlook desktop, clear Office cache by deleting contents of %LOCALAPPDATA%\Microsoft\Office\16.0\Wef.
• Reinstall the Salesforce add-in from Microsoft AppSource or your organization’s centralized deployment.

3. Authentication Method & Modern Authentication:

• Ensure your Exchange Online environment supports Modern Authentication, which the Salesforce add-in requires.
• Confirm that legacy authentication protocols are not blocking the add-in.
• If your organization uses Conditional Access or Multi-Factor Authentication (MFA), verify that policies allow the add-in’s access.

4. Check Microsoft 365 Admin Center & Azure AD:

• Service Health: Check the Microsoft 365 Admin Center (admin.microsoft.com) > Health > Service health. Look for any ongoing incidents related to Exchange Online, Outlook, or authentication.
• Conditional Access Policies: Review any Conditional Access policies in the Microsoft Entra Admin Center (entra.microsoft.com) > Protection > Conditional Access. Look for policies that might be blocking access to "Office 365 Exchange Online" or "Office 365 SharePoint Online" from specific client apps (e.g., "Mobile apps and desktop clients" or "Other clients") or locations. Even if they can log into Salesforce, the policy might block the add-in's direct communication to Exchange.

5. User-Specific & Environment Isolation:

• Test with another user: If possible, try installing and configuring the Salesforce add-in for another user on the same machine. If it works for them, the issue is highly specific to the original user's mailbox configuration.
• Test this user on another machine/Outlook profile: Try setting up the Salesforce add-in for the affected user on a different computer or within a new Outlook profile on their existing machine. This helps determine if the problem is specific to their Outlook installation or their user account/mailbox configuration.

6. Escalate to Support if Needed

If the above steps do not resolve the issue, open a support ticket with both Salesforce and Microsoft.

As forum moderators, we do not have access to backend systems due to privacy and security policies, so we cannot troubleshoot this issue effectively here. It's best to have your Microsoft 365 Global Administrator create a support ticket with Microsoft Support. They have the tools and escalation channels to investigate tenant-specific configuration issues in depth. Go to Microsoft 365 Admin Center>Support>New service request. Provide all details you've shared with me, including the troubleshooting steps you've already performed and the information requested above. The support team there has the correct escalation channel for this case. This is also the most efficient way in handling this kind of issue for you. 

For reference on finding your admin: How do I find my Microsoft 365 admin? - Microsoft Support

For reference: Start using web services in Exchange | Microsoft Learn

I hope this information has clarified the issue and provides workable solutions for your needs. Should you have any further questions or need additional assistance, please don't hesitate to reach out. We're always here to help. Have a wonderful day!

Kind regards, 

Kai-L - MSFT | Microsoft Community Support Specialist

Answer 2

Dear customer,

Just following up to see if the previous suggestions helped resolve the issue. Let us know how things are going, your update would be greatly appreciated!