Big Change to Email Rules from Microsoft

At etac Solutions we work with businesses across the UK to help them get the most out of Microsoft Dynamics 365 Business Central and other ERP services. 

Today, we want to talk about something important that affects how your business sends emails, especially if you send a lot of them.

Microsoft has announced a major change that will start on 5th May 2025. If your business sends more than 5,000 emails a day, Microsoft will start checking more closely whether your emails meet certain rules. If they don’t, your emails may go to the junk folder or even get blocked entirely.

So, what are these new rules and what should your business do to get ready?

What’s changing?

Microsoft wants to make email safer and reduce spam and phishing. To do that, they’re introducing stricter checks on emails sent in large volumes. This means they want to make sure the emails people receive are really coming from who they say they’re from.

To pass these checks, your business emails will need to follow certain technical standards. These include tools like SPF, DKIM, and DMARC.

The key thing to know is this: if your emails don’t meet these standards, Microsoft will start filtering them into junk mail folders. Later, they may stop those emails from getting through at all.

What does that mean for your business?

If your company sends mass emails like newsletters, promotional emails, appointment reminders, or other types of mass communication, this change affects you. This is especially true for businesses in retail, healthcare, finance, education, and any organisation that stays in touch with a lot of customers by email.

Even if you use a third-party email service (like Mailchimp, HubSpot, or a CRM tool), your business is still responsible for making sure these new email rules are followed.

What are SPF, DKIM, and DMARC?

These are three behind-the-scenes tools that help email services like Microsoft Outlook know your emails are legitimate.

• SPF is like a guest list that says which computers or services are allowed to send emails on your behalf.
• DKIM adds a digital signature to your emails - sort of like sealing a letter in a secure envelope.
• DMARC tells email providers what to do if your messages don’t pass the checks and gives you feedback reports so you can fix any issues.

If your business has never set these up, or isn’t sure if they’re working correctly, now is the time to look into it.

What should you do to prepare?

First, you’ll want to make sure your domain has these protections in place. You might need help from your IT team or website provider, as they’ll need to make changes to your domain settings.

You should also check that your emails include a real sender address, one that people can reply to and that they have a clear way for people to unsubscribe. 

Lastly, it’s a good idea to tidy up your email lists. Remove addresses that bounce back or people who haven’t opened your emails in a long time. This helps improve your reputation as a sender and means more of your messages will get through.

If your business relies on email marketing or client communication, this change could have a real impact. Don’t wait until your emails start getting blocked - take action now to stay ahead.