ILN determination: No additional address segment E1ADRE1 with ident. 100

What causes this issue?

To process a PRICAT message on the inbound side, the ILN of the message
sender must be used to determine the SAP supplier number. For this, an
address segment E1ADRM1 with identification FR (= message from) must
exist in the message.
An E1ADRE1 segment belonging to this E1ADRM1 segment must then be
assigned the ILN of the message sender with identification 100 (= ILN).

System Response

ILN determination: no address segment E1ADRM1 with identification FR
exists
or
ILN determination: no additional address segment E1ADRE1 with
identification 100
The IDoc is not processed.

How to fix this error?

Add missing IDoc segments E1ADRM1 and E1ADRE1.

Error message extract from SAP system. Copyright SAP SE.