IncomingEmailS2SApprovalNeeded or IncomingEmailRejected error when you install Dynamics 365 App for Outlook

This article helps you resolve errors that might occur when you try to install Microsoft Dynamics 365 App for Outlook.

Applies to:   Dynamics 365 App for Outlook
Original KB number:   3211621, 3211627

Error: IncomingEmailS2SApprovalNeeded

When you try to install Dynamics 365 App for Outlook, the Status column shows Issue when adding to Outlook. When you select the Learn more link, you see a dialog with the following details:

There was an issue when attempting to add the app to Outlook.
Crm : IncomingEmailS2SApprovalNeeded

Cause

This error can occur if the mailbox record isn't approved by a Microsoft 365 Global Administrator.

Resolution

To solve this issue, approve the mailbox record as a user with the Global Administrator role in Microsoft 365.

1. Sign in to Dynamics 365 as a user with the Global Administrator role in Microsoft 365.

2. Select Settings > Email Configuration.

3. Within the Email Configuration area, select Mailboxes, and then change the view from My Active Mailboxes to Active Mailboxes.

4. Select the mailbox record that encountered the error, and then select Approve Email.

5. After the email address is approved, select the Test & Enable Mailboxes button.

6. After the mailbox has completed testing, try to install Dynamics 365 App for Outlook again. This can be located by selecting Settings > Dynamics 365 App for Outlook.

Error: IncomingEmailRejected

When you try to install Dynamics 365 App for Outlook, the Status column shows Issue when adding to Outlook. When you select the Learn more link, you see a dialog with the following details:

There was an issue when attempting to add the app to Outlook.
Crm : IncomingEmailRejected

Cause

This error can occur due to one of the following reasons:

• The email address for the mailbox record in Dynamics 365 isn't approved.
• The Exchange mailbox is currently linked to another Dynamics 365 organization. An Exchange mailbox (email address) can only synchronize appointments, contacts, and tasks with one organization, and a user that belongs to that organization can only synchronize appointments, contacts, and tasks with one Exchange mailbox.

Resolution

Verify the email address for the mailbox is approved and associated with the desired Dynamics 365 organization.

1. Sign in to Dynamics 365 as a user with the System Administrator role.

2. Select Settings > Email Configuration.

3. Within the Email Configuration area, select Mailboxes, and then change the view from My Active Mailboxes to Active Mailboxes.

4. Select the mailbox record that encountered the error, and then select Approve Email.

5. After the email address is approved, select the Test & Enable Mailboxes button.

6. Within the Test Email Configuration dialog, make sure to select the Sync items with Exchange from this Dynamics 365 Organization only, even if Exchange was set to sync with a different Organization checkbox, and then select OK.

7. After the mailbox has completed testing, try to install Dynamics 365 App for Outlook again. This can be located by selecting Settings > Dynamics 365 App for Outlook.