Office 365 Exchange scanner e-mail outside organization without account

I’m attempting to set up a scanner to send e-mail via an Office 365 subscription (Enterprise E3) to scan to e-mail addresses outside the organization. It can scan to the organizations e-mail addresses without a subscription and authentication but fails to scan to other addresses. Is the only way to make this work to buy a subscription for the scanner if I want to use the SMTP servers offered by Microsoft?

Currently the scanner uses the SMTP server without authentication.

One can add external addresses as contacts in the exchange admin center and that passes mail to the external address.