Sent Items Update

As signatures are added server side (by the CodeTwo Email Azure Service), after an email is sent, they are not visible in the sender's Sent Items folder. To let you see the signatures in the sent mail, we have equipped CodeTwo Email Signatures 365 with the Sent Items Update (SIU) feature. SIU updates your sent messages with signatures after processing by the program. In this article you will learn more about this feature.


The Sent Items Update only works if server-side or combo mode was selected during tenant registration. In the case of combo mode, only server-side messages will be displayed.

How Sent Items Update works

The Sent Items Update works as a separate service and is installed along with the CodeTwo Email Azure Service. SIU needs to be registered in your tenant's Azure Active Directory in order to update Sent Items in the mailboxes of your users.


Sent Items Update is hosted on MS Azure servers. The service is totally independent of your mail flow and the functioning of your Microsoft 365 (Office 365) tenant, which means it has no influence on your email processing and delivery time. Your emails are not stored anywhere. Moreover, Sent Items Update does not require any service accounts to operate as the entire authentication and authorization process uses OAuth 2.0. Learn more about security

Updating sent emails with signatures usually takes a few seconds (it might take longer if the SIU service runs in high-volume or low-performance Azure AD environments).

Which signature is inserted when an email is sent to multiple recipients

When you send an email to multiple recipients, to whom different rules (and signatures) apply, this message is divided into several identical copies, and the software adds a corresponding signature to each copy (learn more). However, you will only see one email in your Sent Items folder. This email will be the message copy that was processed last by the CodeTwo Email Azure Service. What matters is the fact that even though you only see one signature in the Sent Items folder, all of your email recipients get the right signature, based on the signature rules that apply to them.

Emails sent as / on behalf of other users

If you enabled message copying in your Exchange Online, the Sent Items Update works with messages sent by users with delegate (Send As or Send on Behalf) rights to other mailboxes. SIU updates messages in the Sent Items folder of a person who appears to be the sender. See this article for details.

Learn how to assign delegate rights in Office 365

Emails sent as / on behalf of shared mailboxes

If you use shared mailboxes, the SIU works in the same way as described in this section. Message copying needs to be enabled for shared mailboxes.

See this Knowledge Base article to learn more about using the software with shared mailboxes.

How to turn on Sent Items Update

By default, the Sent Items Update service is disabled and needs to be enabled by an admin in the CodeTwo Admin Panel to start updating sent emails.

The Sent Items Update works per tenant, i.e. you have to turn it on for each tenant separately.

To enable the Sent Items Update:

  1. Sign in to CodeTwo Admin Panel.
  2. Enter the management pages of a chosen tenant by clicking the Manage tenant (ESIG for O365 settings button2 13px) button next to the tenant's name.
  3. Go to the Sent Items Update section (Fig. 1.) and click Turn on.


If you do not see the Sent Items Update section, contact CodeTwo Support.

Enabling SIU in CodeTwo Admin Panel.
Fig. 1. Enabling SIU in CodeTwo Admin Panel.

  1. Sign in using your Microsoft 365 (Office 365) tenant global admin credentials.


    Your credentials are completely safe as they are passed directly and only to Microsoft servers, which is ensured by the OAuth 2.0 authorization protocol. CodeTwo does not store, copy or have access to your credentials.

  2. Accept the permissions required for the CodeTwo SIU installer. SIU will be installed.
  3. The Sent Items Update service should start working within a few minutes (in some cases, it can take up to an hour for the service to be deployed).


The updating process starts after an email is passed to EOP, so it may take from a few to over a dozen seconds before a user sees the updated message in their Sent Items folder.

The SIU service only updates messages in the original Sent Items folder. If a user has any OWA/Outlook rules enabled that instantly move messages from the Sent Items folder to another location (including the subfolders of the Sent Items folder), the SIU service will not be able to find and process them. If possible, execute such rules manually or with a delay, to allow some time for the SIU service to update your sent emails.


Messages are not updated in the Sent Items folder

If you already enabled the Sent Items Update service and the messages are not updated, follow the steps below.

  • Check with the recipient if the sender's emails are stamped with signatures at all, to rule out improper signature rules or connectors' configuration as the source of the problem. Also, check the service's status.
  • Sign in to Outlook on the web (OWA) to access your Sent Items folder directly on the server. If you see that messages are updated in the Sent Items folder in OWA, this means the service is working properly and the problem lies in your email client.


If you use Microsoft Outlook, emails in your Sent Items folder might not always be refreshed and displayed correctly. This is usually caused by Outlook's default behavior in the Cached Exchange mode, and is not related to the SIU service. See this article to learn how to solve this problem.

Signatures are not displayed in Outlook on the web (OWA)

Emails in the Sent Items folder are not always correctly displayed in Outlook on the web (OWA). Sometimes to see the signatures you might need to refresh the whole OWA page or open your message in a separate window. This is an Outlook on the web issue, not related to the CodeTwo software. See this Knowledge Base article to learn more.

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