ENR_ASSIGN_OBJECT_NUMBER custom function issue in Vendor master migration

Hello All,

I am using ENR_ASSIGN_OBJECT_NUMBER custom function in Data services for assigning vendor number. I am able to assign numbers in MGMT_NUMBER_ALLOCATION table, But Idoc is failing to load with new number with error  ( Vendor XXXXX not created (please check your input, Error Message No. 06025). I am sure that number which was assigned in MGMT_NUMBER_ALLOCATION is not in vendor master, please let me know how to overcome this error and load Idoc's successfully.

Target : SAP ECC

Source : AS400

Staging : SQL

Thanks in advance!