toRecipients list of the NDN message contains email addresses of the recipients that failed:
User with email address "user@test.com" sends email to an invalid (non-existing) email address "aaa@test.com". Then this user recieves a Non Delivery Notification. Outlook 365 web client displays NDN correctly and "TO" field contains email "user@test.com". But MS Graph Message object contains toRecipients list with "aaa@test.com" inside instead of the real recipient of this NDN message - "user@test.com".
Please, advise, how to identify the real "toRecipient" for such messages? And how to identify that the message is Non-delivery notification?
Thanks.