Not received confirmation mail on ownership transfer of Drives and Docs

[Ajay10]

Hi all,

I have performed ownership transfer of Drives and Docs from one user (xy@test.com) to another user new owner (ab@test.com) via REST call. The REST call is successful and ownership transfer is also successful, but the New owner(ab@test.com) or the previous owner (xy@test.com) didn't received any confirmation mail on ownership transfer... Below is my set up

xy@test.com is Active and present in 'ABC' OU 

ab@test.con is Active and present in 'DEF' OU.

Is there anything am I missing??

Thanks in advance.