When you use the Office365 Outlook Email send adapter to send email messages, you notice that the messages get suspended, and the following error message is generated:
An unexpected failure occurred when processing a message. The text associated with the exception is "Object reference not set to an instance of an object."
Note This error does not prevent the email messages from being sent. The same messages may get sent multiple times if the send port retry count is greater than 0.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
This problem is fixed in the following cumulative update for BizTalk Server:
Cumulative Update 3 for BizTalk Server 2020
For information about the service packs and cumulative update list for BizTalk Server, see the following article in the Microsoft Knowledge Base:
2555976 Service pack and cumulative update list for BizTalk Server
For more information about BizTalk Server hotfixes, see the following article in the Microsoft Knowledge Base:
2003907 Information about BizTalk hotfixes and Cumulative Update support