Office365 is very particular about how email can be sent through the accounts they host.  Configuring Airstudio as a Web App -> Office365 requires a higher level of authentication than a normal SMTP or IMAP connection.  These are the sending specs and limits:

Setting up your hosted email will require one of our techs to work with you one on one-to-configure a service account in their azure account for the API authentication.  For that service we charge $200.00 / hour and I would estimate it to take no more than an hour.  We also offer other email options through Airstudio.  We handle all of the email sending at no charge from [email protected] (your account is configured in this way when delivered) or for $10.00 / month for we will create a [email protected] (replies to this will auto forward to whatever account you specify).

Detailed Technical Instructions for Office365 Azure:

For Office 365 (Microsoft 365) API authentication you configure Microsoft Entra ID (Azure AD) and use OAuth 2.0 tokens to call the API you care about (usually Microsoft Graph). (Microsoft Learn)

1) Decide which auth flow you need (this drives the setup)

A) App runs without a signed-in user (service/service, background jobs)

Use Client Credentials (app-only). Typical for daemons, server-to-server, scheduled jobs. (Microsoft Learn)

B) App acts on behalf of a signed-in user (web app, interactive)

Use Authorization Code Flow (use PKCE for public clients like desktop/mobile). (Microsoft Learn)

C) “Legacy protocols” (IMAP/POP/SMTP) against Exchange Online

Still OAuth 2.0, but the configuration and scopes differ from Graph mail APIs. (Microsoft Learn)

If you tell me which of A/B/C you’re doing, I can tailor the exact permissions + endpoints, but below is the common baseline that works for most Graph/API scenarios.

2) Register your app in Microsoft Entra ID

  1. Go to Microsoft Entra admin center → Identity → Applications → App registrations → New registration. (Microsoft Learn)
  2. Choose: