Signatures for some users fail to upload and an EWS error is logged in the Exclaimer event logs. – Exclaimer Knowledge Base
ExchangeImpersonation SOAP header must be present for this type of OAuth token. · Issue #245 · OfficeDev/ews-managed-api · GitHub
![c# - Exchange (EWS SOAP) Get Folder with Impersonation return 500 - Invalid Request - Stack Overflow c# - Exchange (EWS SOAP) Get Folder with Impersonation return 500 - Invalid Request - Stack Overflow](https://i.stack.imgur.com/0Juoy.png)