We have an application internally that runs as a service account (which connects to exchange online via EWS) that sends emails on behalf of the user logged in. About 10 days ago it stopped working,
We can log into OWA or outlook with the service account and send from other accounts so I know the permissions are still valid.
The application support asked us to check if the service account had the rights for
ms-Exch-EPI-Token-Serialization because they were seeing the error in their logs about the user not having the rights to serialize tokens.
I can only find powershell commands for on prem exchange, nothing for exchange online.
thanks,jb
