BizTalk AS2: asynchronous MDN error with 202 Accepted

When integrating with GXS OpenText, I recently encountered an issue with an AS2 setup.


  • You receive an inbound message over AS2.
  • The AS2 client is setup to receive an asynchronous MDN regardless of the use of a encryption/signing or compression.
  • ¬†You’ve setup a two-way send port to send out the asynchronous MDN.
  • The two-way send port uses AS2Send and AS2Receive pipelines.

With this setup, we encountered the following AS2 error:

An output message of the component “Microsoft.BizTalk.EdiInt.PipelineComponents” in receive pipeline “Microsoft.BizTalk.EdiInt.DefaultPipelines.AS2Receive, Microsoft.BizTalk.Edi.EdiIntPipelines, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35” is suspended due to the following error:
An AS2 message was received that did not contain the AS2-From header..
The sequence number of the suspended message is 2.

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