RCVPOR empty in ERP System

Dear all,

I have a file2IDOC scenario in PI 7.11 and have a strange behaviour.

We send 3 different IDOCs to ERP system. Two seem to work without error, but a STATUS.SYSTAT01

IDOC arrived in ERP without RCVPOR and failed.

We are using the same IDOC Inbound channel for all IDOC types where following options are actived:

Queue Processing

Apply Control Record Values from Payload

Take Sender from Payload

Take Receiver from Payload

I hard coded even the value "SAP<ERP>" in mapping and see in outbound message that it is filled, but even

I deselect the Option "Take Receiver from Payload" and enter the Port in channel.

I don't understand why the port is filled in one Idoc Type and not in STATUS Idoc.

Is there anything else an option I missed?

regards

Chris