Change IP to Email-address

Hi,

In Server-U a colleague sent data to different (email) users. When one of a client (receiver) download the file, we want to now witch user have downloaded the file. Now we see only a IP address below Location in Server_U client.(See picture below)

How can we change this to a email-address.

The release we use of Server_U = 15.1.5

Regards EmmtecS