Change Word Mass Mailing Sender

Question

I'm using the Fusion & Mailing tool on Word.

I've set up 3 mails adresses in my Outlook.

I've noticed that Word sends the mails with an adress which is the first one I entered on my Outlook.

When I change this address on my Outlook and make another one "by default", the mails are not received nor sent (I'm using GMail and a custom adress hosted by OVH).

How can I make the mails sent by Word be sent by the GMail adress or the OVH hosted adress and get them in my Received and Sent message in the mailboxes ?