Challenge
When adding or editing an Office 365 organization, the following unexpected error occurs: "Connect to EWS: SOAP header Action was not understood".
Cause
The error may occur when establishing a connection to the Exchange Web Services (EWS).
Solution
As a workaround, you can temporarily assign a mailbox to your service account that is used to add or back up an Office 365 organization.
If you cannot assign a mailbox to your service account due to license limitations, contact Veeam Technical Support.