Event/webinar registration confirmation emails go to junk email

Paiju 0 Reputation points
2026-09-04T11:40:39.6433333+00:00

Hi. I've created an event (with your new Events apps), and I have just found out the registration emails are going to junk. Can you help me resolve why that is?

Microsoft Teams | Microsoft Teams for business | Meetings and calls | Schedule meetings
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  1. Michelle Nguyen 1,180 Reputation points Independent Advisor
    2026-09-04T12:14:24.12+00:00

    Hi @Paiju

    Based on your description, I understand that: you recently created an event using Teams Events, and after publishing it, you discovered that the automated registration confirmation emails sent to attendees are being delivered to their Junk/Spam folder instead of their inbox, meaning registrants may be missing their confirmation and event access details entirely.

    A few things I'd recommend trying in the meantime:

    1. Send yourself a test registration and check the message headers for the Spam Confidence Level (SCL), this will help us determine whether it's a reputation-based filtering issue or a content-based trigger.
    2. If the affected registrants are in your own tenant, your admin can allow-list the relevant Dynamics 365 email delivery IP ranges in the Anti-spam Connection filter policy (Microsoft 365 Defender portal).
    3. For external registrants, ask them to add the sender to their Safe Senders list, or have their IT allow-list the sending domain/IP ranges.
    4. Consider adding a short note on your registration page letting attendees know to check Junk and mark the sender as safe, until this is resolved.

    Beside that, could you confirm:

    • Approximately when this started (was it working fine before)?
    • Whether it's happening across different recipient domains or just specific ones?
    • Whether anything changed on your event setup recently?

    That will help narrow down what's causing this in your case. Thanks for your patience.

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  2. AI answer

    2026-09-04T11:40:54.78+00:00

    Registration confirmation emails for Teams webinars and events are sent by the email delivery service in Microsoft Dynamics 365. If external email security policies are configured in the tenant, those messages can be quarantined by the spam filter and end up in Junk.

    Use this check-and-fix path:

    1. In Teams, open the webinar or event from the Teams calendar.
    2. Go to Registration > Attendee status.
    3. Check the attendee’s registration state:
      • Pending approval: registration is not complete yet. If Require manual approval of all event registrations is enabled, select Approve. The confirmation email with the join link is sent only after approval.
      • Waitlisted: the event is at capacity. The email will not be sent until a spot opens or capacity is increased.
      • Confirmed: if the attendee used the correct email address and still did not receive the confirmation, allow the public IP addresses used by the Dynamics email delivery service in the spam filter.

    If messages are still being filtered:

    1. Open the Anti-spam policies page in Microsoft 365 Defender: Anti-spam policies.
    2. Select Connection filter policy (Default).
    3. In Connection filtering, select Edit connection filter policy.
    4. Turn on Always allow messages from the following IP addresses or address range.
    5. Add one of the IP addresses used by the email delivery service, confirm the full value, and select Save.
    6. If prompted to enable customization, select Yes.

    If customization is disabled:

    • Wait a few hours and try again, adding one IP address range first.
    • If that still fails, connect to Exchange Online PowerShell and run Enable-OrganizationCustomization, then add the remaining IP ranges and save.

    This issue is typically caused by tenant spam filtering rather than the event registration feature itself.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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