Short answer:
If a user is not created in Xink, the Outlook add-in will not apply a signature and may show an error. The user can ignore the message and continue using their own signature. To avoid this, limit deployment to Xink users or adjust the deployment method.
If a user does not exist in Xink and the add-in is installed, their own created signature will remain. However, they may see the error shown below. This message can be ignored, and the user can continue using their existing signature.
Recommended approach:
Create a group for your Xink users and deploy the add-in using "Specific users/groups". This ensures that only users configured in Xink receive the add-in.
Alternatively, you can change the deployment method to "Available", which allows users to install the add-in themselves, but this requires user interaction.
Android-specific note:
If this error occurs only on Android, it typically means the UPN differs from the SMTP address. This scenario is not supported due to Microsoft limitations. See the Manifest Deployment Guide for more details.
Workaround:
Create a copy of the user with an email address that matches the UPN, or configure a server-side setup so the signature is applied after the email is sent. Learn how to configure server-side signatures.
