I can't manage to give Brevo's sender ID field what it wants

Hi

I have an issue with a Brevo automation on Make.
I’m selecting the “Create an Email Campaign” module and it wants multiple fields to work.

To compare two key fields in my use case : the Sender field and the Segment field.
For both i’m trying to use (ignore the “//”, the markdown makes the open and close brackets into squares without them…)
Segment : {{4.items[//].Segment envoi[//].value}}
Sender : {{4.items[//].Mail envoi[//].value}}

and it works for the Segment field but not for the Sender field ! (and yes, the data is of the same type for both cases)

Can anyone help me ?