We want to send 5000 newsletters from our M365 mailbox
Microsoft 365 isn't a marketing platform. Limits are 10,000 recipients per day per user and 30 messages per minute. Bulk from a regular mailbox has no one-click-unsubscribe, no suppression list and gets flagged often. Don't do it. Use an ESP.
Try this first
- 1Do the math: 5000 recipients per newsletter once a month is probably within limits, but without any protection against reputation damage.
- 2Pick an ESP for marketing: Postmark for transactional, Brevo or Mailchimp or Campaign Monitor for newsletters, ConvertKit for B2B content. All GDPR-compliant with EU hosting available.
- 3Set up a dedicated subdomain for marketing: news.yourdomain.com with its own SPF, DKIM, DMARC. Keeps reputation separate from transactional.
- 4Import only opt-in contacts. Don't copy lists from LinkedIn or a stack of business cards.
- 5Enable one-click-unsubscribe (RFC 8058) by default. Required since February 2024 for Gmail/Yahoo bulk.
When to bring us in
If you mix transactional and marketing through one path, every spam complaint on marketing pulls your transactional reputation down. Split paths first.
See also
- Our emails land in spam for some recipientsAlmost always an SPF, DKIM, or DMARC setting that is wrong or missing, or a sender name that mimics a well-known brand.
- Someone reports receiving phishing emails "from us"Read: spoofing. Someone is abusing your sender name, not necessarily your actual mailbox.
- An email bounces (NDR): delivery failedThe NDR text usually states the exact reason. Reading it is step one.
None of the above fits?
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