Buy lookalike or backup domains (GoDaddy, Porkbun, etc.).

Create one Microsoft 365 account per domain to minimize risk.

Do not create more than 3 inboxes per domain.

Go to https://www.microsoft.com/en-us/microsoft-365/business

Choose a "Business Basic" plan or equivalent.

Add your domain during the setup.

Create an admin user for the workspace.

Keep a spreadsheet with inbox credentials and domain mapping.

Go to the Microsoft 365 Admin Center.

Verify your domain by following Microsoft’s DNS instructions.

Set up your mail exchange (MX) records to enable Outlook email.

In the Admin Center, go to Users > Active Users.

Select a user > Mail tab > Manage email apps.

Enable IMAP and Authenticated SMTP.

Save changes.

Repeat for all inboxes.

SPF: Add this TXT record to your DNS:
​v=spf1 include:spf.protection.outlook.com ~all

DKIM: Go to Microsoft 365 Defender Portal > Policies & rules > Threat policies > DKIM.

DMARC: Add a TXT DNS record: v=DMARC1; p=quarantine; rua=mailto:[email protected]; pct=90; sp=none

Users can upload their profile picture via their Microsoft account.

This can help improve trust and email appearance.

Go to Microsoft Admin Center > Azure Active Directory > Enterprise Applications.

Click "+ New Application" > "Create your own application" > Add Prospi.

Under Permissions, allow the scopes requested by Prospi.

Grant admin consent to finalize integration.

In Prospi, go to Email Accounts > Add Account.

Select Microsoft.

Complete the OAuth authorization flow.

Once approved, inbox will appear in your account list.

Head to the Email Accounts page.

Confirm inbox is connected and authorized (green checkmark).

Warm-up will start automatically.

Inboxes are now connected and warming up.

You can connect up to 3 inboxes per domain, with 10–60 inboxes depending on your Prospi plan.

Allow 2 weeks of warm-up time before launching campaigns.