ArchiOffice/EngineerOffice 20xx is a web-based application built using Microsoft .Net technology. To send emails using Office 365 in ArchiOffice/EngineerOffice, you need to set up an SMTP relay.
SMTP relay lets Microsoft 365 or Office 365 relay emails on your behalf by using a connector that's configured with your public IP address or a TLS certificate.
To set up an SMTP relay, click here for details. Scroll down to Option 3: Configure a connector to send mail using Office 365 or Office 365 SMNTP relay and follow the instructions.
After the relay is set up, emails can be sent out through the IP specified in the Mail Flow Connector of the instructions.