Problem
You wish to use Outlook message recall with Signature 365 and would like to know if Signature 365 supports this functionality.
Solution
Signature 365 supports the message recall feature present in Microsoft Outlook, but there are a number of restrictions you must be aware of:
- We recommend that client-side signatures are used where message recall is required - the Outlook Addin cannot have any effect on message recall. Please see the additional information section.
- This functionality is not supported by Microsoft with emails sent to external recipients.
- Emails that have already been marked as "read" or opened cannot be recalled. Only unread messages will be recalled or replaced.
- If a recipient opens the original message before reading the recall message, the recall will automatically fail.
- If the recipient moves the email to another folder on receipt but does not move the recall, the recall will automatically fail.
- An email can be considered "read" by Outlook if it has been synced to a mobile device and not read by the recipient.
- Message recall does not work with class lists or groups.
- Both sender and recipient must be using Outlook for Windows. Outlook for the Web and Outlook for Mac does not support this functionality.
- Message recall requires both the sender and recipient to belong to the same Microsoft 365 Tenant. If you have internal staff using mail accounts such as Gmail, this will not function.
- Microsoft are currently in the process of implementing an improved version of message recall.
Additional Information
Outlook message recall uses a MAPI property to correctly identify the message to be recalled in the recipient's mailbox.
When an email is routed via an external connector, as is the case for server-side signatures, this property is likely to be updated causing the message recall to fail.
The functionality cannot be changed as confirmed by Microsoft. We recommend using client-side signatures using the Outlook Add-in if you require message recall for a specific user.
To increase your chances of message recall functioning where emails must be sent via the Signature 365 connectors, you must ensure that you configure your Remote domains settings in Exchange Online by following Enable TNEF for a remote domain in Exchange Online