2729826 - Mandatory partner function xx is missing for sales area

Uploading customer master data with sales partners information using the SAP Migration Cockpit the following error occurs:

Mandatory partner function XX is missing for sales area XXX XXX

S/4HANA Cloud
SAP Migration Cockpit

Try to upload customer master data with sales partners information using the SAP Migration Cockpit.

There are two typical root causes for this issue:

1, Language dependent partner function name (SP, SH, PY, BP or ER) is used instead of language independent name (AG, WE, RG, RE or ZM).

2, "Sales Partner" sheet of  template is filled, but with only one mandatory partner function.

1, Read the actual tooltip of the column header "Partner Function" in the migration template:

2, Need to provide all mandatory partner functions or none.

2a, Leave the "Partner Function" sheet empty. In this case as described in the Mapping Instructions:
"The mandatory partner functions will be created automatically with the same customer number."

2b, Provide all mandatory partner functions (RE, RG, WE and AG) with the same customer number.

KBA 2609888 - Mandatory partner function SP is missing for sales area

LTMC, vendor, supplier, MDG_BS_ECC_BP_CHECK040, MDG_BS_ECC_BP_CHECK 040, TPAKD, Business Partner: Valid Acct Groups per Partner Function , KBA , CA-GTF-MIG , SAP S/4HANA Data Migration Cockpit Content (LTMC) , Problem