Please maintain the field 'Sequence'

What causes this issue?

You have specified the source partner function as different from the
sold-to party, however you have not adapted the partner determination
sequence.

System Response

The system can not determine the partner.

How to fix this error?

In the <LS>sequence </> field enter a number, which is higher than the
partner function figure that you entered as the source partner
function.
Example:
The sequence <LB>0 </> is entered for the function SH (ship-to party).
If you have entered the function SH for the contact person (CP), also
enter this in the field <LS>sequence</> <LB>1 </>. The system then
determines the ship-to party and afterwards the contact person from the
ship-to party master record.

Error message extract from SAP system. Copyright SAP SE.