Problem with File to IDOC scenario

Hello,

I try to implement our first scenario to IDOC.

In TOC SXMB_MONI I have to errors

1. <SAP:Code area="IDOC_ADAPTER">ATTRIBUTE_INV_SND_SERV</SAP:Code>

2. <SAP:Stack>Unable to convert sender service aaa_Sender_Service to an ALE logical system</SAP:Stack>

Any idea how I can solve this problems?

Elad