Biztalk BTAHL7 batching - cannot start a Batch process

We installed Biztalk 2020 and its HL7 accelarator. I'm trying to setup a HL7 batching based on this article from Microsoft.

First I made sure I started the Batch Orchestration and its receive port from within Biztalk Application 1

Next I created a party call Test and assign it a Send Port.

After Restart the Biztalk host instance to make sure the changes are applied, I brought up the BTAHL7 Configuration Explorer and go to the "Test" party to start the HL7 batching.

whenever I start a batch, I keep getting error on the BatchControlPort.

The way I think this implies to me is the BatchOrchestration.Orchestration_1 orchestration received a signal to tell it to start a batching process for the party Test but since it found no subscribed send/receive port, it stops right away and display the error.

I modified my send port to only subscribed to the BTAHL7MessageType == OutboundBatch, meaning this port is listening to any batching process that finished so I'm kinda baffle that Biztalk keeps telling me there is no subscriber.

Based on what you see me done so far, do you see I miss any steps? I'm at a point where I cannot get a batching process started, I don't even touch any message to be batched yet.

It turns out that when you start a party's batching via the BTAHL7 Configuration Explorer, it generates a small HL7 message and put it into the directory where the receive port BatchControlLocation is monitoring, in the case of Biztalk 2020 it is under C:\Program Files (x86)\Microsoft BizTalk Accelerator for HL7\CreateBatchFileDrop*.*

This receive port is automatically created by the Biztalk Accelerator installation but by default it is set to PassThroughReceive which does not do anything to read HL7 format message.

Upon me changing the receive pipeline to BTAHL72XReceivePipeline then now it can read that trigger HL7 format message and I can now see my newly created batch process for party Test under the dehydrated orchestration list.