We experiance a weird issue after upgrading Aspose.Email.dll from version 3.8 to 17.12.
We use Aspose.Email to generate some mails to customers with a sender (from) a shared e-mailadress like email@example.com these are sent either automatically by “the system” or they are prepared for the user to send through Outlook. Either way they are sent through an Exchange server in the cloud.
This worked fine using version 3.8 but after upgrading to 17.12 the Exchange server rejects the mails with the message “This message could not be sent. Try sending the message again later, or contact your network administrator. You do not have the permission to send the message on behalf of the specified user. Error is [0x80070005-0x0004dc-0x000524].”
There are several posts on the net regarding this error message and ways to resolve - for instance this one:
[Issue and several suggestions for solution] (http://www.admin-enclave.com/en/articles/exchange/292-resolved-you-do-not-have-the-permission-to-send-the-message-on-behalf-of-the-specified-user.html)
Are some of these adjustments to the Exchange server needed when we use version 17.12 to create the mails instead of version 3.8?
Or was there some MAPI-headers automatically set by the version 3.8 that we need to add explicitely in version 17.12?
For reference - we made to seemingly harmless and straightforward code changes when changing the version.
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The people managing the Exchange-server setup are reluctant to change anything as “It used to work fine” and when a user opens the mail, changes the sender of the mail by selecting the same email from their addressbook they are able to send the mail.
Any hint or help is much appreciated.
NB There seems to be some relation to this topic (no conclusion there though): Related topic