Main Question: How can I use EWS from an outlook Addin to send emails on behalf of another mailbox. I am sending emails (creating and replying) from a centralized account but I want it to look like its coming from one of the many clients accounts that we have. Which account credentilas do I use in creating the Exchange object
Additional Info: So far I have been able to connect to EWS within the Addin (witha domain user account) but connecting to the client mail boxes and sending on behalf of has proven a challenge For each client, Exchange team (ET) created disabled mail user object without an account to log on, currently about 101 of them. Then ET also created a single centralized mail box with the aim of managing the emails for the multiple client mail boxes (each with its own unique emailaddress) as folders from a single centralized mail box using forwarding (from the client mail boxes upon arrival of the mail) and rules to route the mails to the specific folders within the main box.
Insight, thoughts much appreciated