Sent by or Sent on behalf on shared Mailbox

Dear experts, 

I have connected a shared mailbox to power bi using the PBI MS Exchange Online connector. 

My problem is that in order to measure productivity, I am missing the fields Sent by or Sent on behalf, to identify which employee sends what.

Is there a way to get this information? Anything that I have to activate on the inbox so this information is accessible?

thank you in advance