Please share office 365 mail configuration 

Have raised a ticket for your request, our team will reach out to you regarding this.

FYI: We have a single Exchange Online (Plan 1) mailbox called and with the email address do-not-reply@ourdomain.com

No config was needed at the M365 end as it was using a user mailbox to authenticate with m365 SMTP service. 

This was our config in Pulseway > Server Admin > Email > Server Settings