I got the Person Number from a transaction and with the person number and the address number, I am able to get the email id from ADR6 table. But now, I want to get the SAP UserID of the same person. I tried querying USR21 table with the same Person Number and it is returning failed. I checked the table USR21 manually with the username and found that the Person number there is different as from the person number in ADR6 table. How can this be possible? How can I get the email and userid from the person number and address number?