Problem
OWA signatures are not updating in Office 365 even though deployment is successful and there are no errors in the Status Monitor in Email Signature Manager.
Reason
Microsoft enabled the roaming signatures feature on all Office 365 tenants in April 2023. This update disables existing documented functionality to set OWA signatures in code using Exchange Web Services (EWS) or using their Set-MailboxMessageConfiguration cmdlet, as described in the following Microsoft article:
Email Signature Manager leverages this functionality to update OWA signatures. As a result, this feature cannot function unless roaming signatures are disabled by Microsoft for your organisation.
Recommendation
Microsoft strongly recommends against disabling roaming signatures, and Symprex does not recommend this method due to future deprecation of features by Microsoft.
Please note: Version 9.5.1 or later of Email Signature Manager is required for OWA signatures to be set.
Microsoft have created the following Powershell command to enable roaming signatures to be postponed on a Microsoft 365 tenant.
Set-OrganizationConfig -PostponeRoamingSignaturesUntilLater $true
To confirm this has been disabled check the following
1. Logon to OWA
2. Open Settings, select Email and select Compose and reply.
3. If your Compose and reply settings include the option to add signatures clicking + New signature then the roaming signatures feature has been enabled on your Office 365 tenant:
Applies to
Email Signature Manager, all versions