Choose a supported Microsoft method
Keep the included email service active unless your Microsoft 365 administrator approves a compatible relay. Microsoft supports several application-mail paths, and the correct choice depends on tenant policy, volume, network ownership, and whether OAuth is required.
- Authenticated client submission increasingly uses OAuth rather than reusable mailbox passwords.
- Microsoft 365 SMTP relay uses an Exchange Online connector and normally requires a static, unshared public IP address or certificate. It must be reviewed before use from a hosted multi-tenant service.
- Azure Communication Services Email and Microsoft high-volume email are separate services with their own onboarding and limits.
Use an approved relay with this portal
- Ask the Microsoft 365 administrator which application sending method is approved and whether it exposes a standard SMTP endpoint compatible with this page.
- If an Exchange Online connector will identify the service by source IP or certificate, contact DMTG Tech before creating the connector. Do not authorize an undocumented shared address range.
- Enter only the hostname, port, connection security, and credentials supplied for that approved relay.
- Use a From address the connector is permitted to send, then save and test before activation.
When your policy requires OAuth
Microsoft app registration uses authorization grants, tenant consent, protected refresh tokens, and scoped Exchange permissions. A client ID, client secret, or OAuth token is not an SMTP password. Do not paste any of those values into Custom email settings.