How to fix email send out erro 550 5.7.236

Loh 10 Reputation points
2026-02-05T09:23:06.61+00:00

Domain user : [Moderator note: personal info removed] .com

Send out error

Remote server returned "550 5.7.236 Your message can't be sent because your tenant has exceeded its daily limit for

Exchange | Other
Exchange | Other

A powerful email and collaboration platform developed by Microsoft, designed to support enterprise-level communication and productivity. Miscellaneous topics that do not fit into specific categories.

Locked Question. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

4 answers

Sort by: Oldest
Most helpful Newest Oldest

  1. AI answer

    2026-02-05T09:23:14.33+00:00

    The error code 550 5.7.236 indicates that your message cannot be sent because your tenant has exceeded its daily limit for sending emails to external recipients from your organization's onmicrosoft.com domain. This limit is enforced to prevent abuse and is set to 100 external recipients within a 24-hour rolling window.

    To resolve this issue, consider the following steps:

    1. Wait for the Limit to Reset: The external recipient limit is tracked over a 24-hour rolling window. You can resume sending messages once the count for the most recent 24-hour period falls below the limit.
    2. Use a Custom Domain: If you frequently need to send emails to external recipients, consider purchasing and migrating to a custom domain. This will help you avoid the limitations imposed on the onmicrosoft.com domain.
    3. Monitor Your Sending Patterns: Keep track of how many external recipients you are emailing to avoid hitting the limit in the future.

    If you continue to experience issues, you may need to contact Microsoft support for further assistance.

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

    Was this answer helpful?

  2. Hin-V 16,830 Reputation points Microsoft External Staff Moderator
    2026-02-05T11:59:59.05+00:00

    Hi @Loh

    Thank you for posting your question in Microsoft Q&A. 

    Please note that our forum is a public platform, and we will modify your question to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data.

    As my research, the error code "550 5.7.236" is thrown when emails are being sent from an onmicrosoft.com domain, and the tenant has reached Microsoft’s external sending limit. The outbound mail sent from default onmicrosoft.com (MOERA) domains is throttled to 100 external messages per 24‑hour rolling window. Once that limit is reached, Exchange Online blocks further messages and returns this error.  

     User's image

    Reference: Email non-delivery report (NDR) and SMTP errors in Exchange Online - Exchange | Microsoft Learn 

    As AI suggestion, you could try to: 

    Wait for the 24‑hour rolling window to reset 

    Once your tenant falls back below the limit, sending will resume automatically.  This usually resolves itself within a few hours depending on when emails were sent. 

    Using a custom domain 

    To prevent this issue from recurring, you may want to consider implementing a more permanent solution by shifting your outbound email traffic to a custom domain. Microsoft enforces strict limits on the default onmicrosoft.com domain, capping it at 100 external emails per 24‑hour rolling window, and strongly recommends using a custom domain to avoid throttling and improve overall email deliverability. 

     User's image

    You can refer via: 

    Limiting Onmicrosoft Domain Usage for Sending Emails | Microsoft Community Hub 

    I hope this helps. 

    Please feel free to correct me if I misunderstood your request. If you have any additional concerns, feel free to comment below. I would be more than happy to assist.  

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".      

    Note: Please follow the steps in [our documentation] to enable e-mail notifications if you want to receive the related email notification for this thread. 

    Was this answer helpful?

    1 person found this answer helpful.
  3. EmilyS726 272.9K Reputation points Independent Advisor
    2026-02-05T13:32:13.55+00:00

    This means your tenant has reached the daily send limit, you have to wait 24 hours.

    What domain do you use? Do you use your own custom domain, or do you use Microsoft's onmicrosoft.com domain?

    Was this answer helpful?

    0 comments
  4. Nicoleta Ursache 0 Reputation points
    2026-04-09T20:07:36.1566667+00:00

    Hi!

    I experienced the same error, but in my case the external recipient limit was NOT exceeded.

    The issue was caused by a backup/storage system (QNAP/Altaro) sending email notifications every 1–2 seconds to a mailbox in the tenant.

    This high-frequency sending appears to have triggered throttling/abuse protection, which blocked or delayed mail flow, even though the daily recipient quota was not reached.

    Was this answer helpful?