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Microsoft 365 and Outlook business email setup

Microsoft 365 gives your team Outlook with your company address, plus Teams, Word and Excel. Setting it up correctly (domain, DKIM, security and devices) is what keeps your email trusted and safe.

Updated · 2 min read · By the ZeroSpams team

The short answer

We set up Microsoft 365 email for your business: add and verify your domain, create mailboxes and shared mailboxes, configure MX and the other DNS records Microsoft requires, switch on DKIM signing, add SPF and DMARC, turn on security defaults and two-step sign-in, and connect Outlook on phones and computers.

What’s included

  • Domain setup and the DNS records Microsoft requires.
  • Mailboxes, shared mailboxes (info@, sales@) and distribution groups.
  • DKIM switched on for your domain, with SPF and DMARC.
  • Security: two-step sign-in, admin roles, anti-phishing settings.
  • Outlook on Windows, Mac, iPhone and Android.
  • Migration of existing email (optional).

How we do it

  1. Set up or take over your Microsoft 365 tenant.
  2. Add and verify your domain.
  3. Authenticate: DKIM, SPF and DMARC.
  4. Create mailboxes and security settings.
  5. Connect Outlook and test.

Sending to Outlook.com and Hotmail

Since May 2025, Microsoft rejects email from high-volume domains that fail SPF, DKIM or DMARC with the error "550 5.7.515" [1]. Your own Microsoft 365 setup should pass all three; we make sure it does.

Common questions

Do we need Microsoft 365 to use Outlook?

No, Outlook works with other providers too, but Microsoft 365 gives the most complete Outlook experience, with shared calendars and mailboxes.

Can shared mailboxes be used without an extra licence?

Microsoft offers shared mailboxes without a separate licence within certain limits; we’ll advise on what fits your team.

Can you move us from Google Workspace?

Yes, in either direction. See business email migration.

Sources

Numbers in this guide come from these studies and publications. Links open the original.

  1. Strengthening Email Ecosystem: Outlook’s New Requirements for High-Volume SendersMicrosoft Defender for Office 365 blog, Microsoft Tech Community, 2025Since 5 May 2025: SPF, DKIM and DMARC required for domains sending 5,000+ emails a day to Outlook.com, Hotmail and Live.