How to Set Up Multiple Microsoft 365 Accounts for Cold Email

Microsoft 365 is the second most popular email provider for cold email. Here is how to set up multiple accounts.

Creating accounts

In the Microsoft 365 Admin Center, go to Users > Active Users > Add a User. Enter the user's name and email. Assign a license (Exchange Online is the minimum required license for email).

Configuring authentication

Enable DKIM for your domain through the Microsoft 365 Defender portal. SPF is configured in DNS with Microsoft's include statement. DMARC is configured in DNS as described in Article 113.

Microsoft-specific considerations

Microsoft 365 is more aggressive about detecting suspicious behavior on new accounts. New accounts should be warmed more slowly (see Article 99). Enable multi-factor authentication on all accounts — Microsoft may restrict accounts without MFA.

Account security

Microsoft occasionally requires re-verification for accounts that send high volumes. Keep account credentials secure and MFA enabled to avoid security-triggered suspensions.

Choosing between Google Workspace and Microsoft 365

Both providers work well for cold email. Google Workspace is slightly more popular in the cold email community and has marginally better deliverability to Gmail (the largest recipient provider). Microsoft 365 has strong deliverability to Outlook and corporate recipients. Some scaled operations use both providers for diversity. Warm Inboxes offers pre-warmed accounts on both platforms.

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