Share via

outgoing email issue

paulandjanis 0 Reputation points
2026-05-08T20:45:58.7733333+00:00

some emails we send show delivered, but the recipient says they did not receive

Outlook | Web | Outlook on the web for business | Email
0 comments

2 answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Vy Nguyen 11,070 Reputation points Microsoft External Staff Moderator
    2026-05-08T21:36:33.1833333+00:00

    Hi @paulandjanis, 

    I hope you’re doing well today. 

    Based on the information you shared that some outgoing emails display a Delivered status, however the recipients confirm they did not receive the messages.   

    In Microsoft 365, Delivered generally confirms the message was accepted by the recipient’s mail system, and then the recipient’s environment may still route it through filters, quarantine, mail flow rules, or mailbox rules before it appears in the Inbox. Therefore, the next steps focus on identifying the exact point where the message was accepted and what happened afterward. 

    Below is a clear and detailed guide to walk them through the steps that can restore your user’s ability to receive emails. If they don't have a permission, please tell them to contact their IT's administrator to follow this steps below:   

    1/ Run message trace (admin only) 

    2/ Review mail flow rules and anti-spam settings   

    Sometimes, mail flow rules or spam filters may prevent emails from reaching the inbox.  

    • Go to the Exchange Admin Center.  
    • Navigate to Mail Flow > Rules and check for any rules that might redirect or block incoming emails.  
    • Also review Anti-Spam Policies under Microsoft 365 Defender > Policies & Rules.  

    Make sure there are no filters or rules targeting the affected user’s mailbox. 

    3/ Check accepted domains:  

    • In EAC, go to Mail flow > Accepted domains.  
    • Ensure that the user's email domain is correctly listed as an "Authoritative" accepted domain. If it's not, or if there's a misconfiguration, it could prevent incoming mail.  

    4/ Check individual mailbox settings:  

    • Junk Email Settings (Outlook/OWA): While less likely to completely block all incoming mail, an aggressive junk mail setting or a large "Blocked Senders" list could be preventing legitimate emails. Have the user check their own blocked senders list in Outlook/OWA.  
    • Mailbox Quota: Is the user's mailbox full? If so, they won't be able to receive new emails. Check their mailbox quota and usage in EAC under Recipients > Mailboxes.  

    5/ Check for Account Restrictions  

    After an account compromise, Microsoft may automatically restrict email capabilities to protect the environment.  

    • Visit the Restricted Users page: Security & Compliance  
    • If the user appears on this list, follow the prompts to remove the restriction.  

    This action ensures the account is no longer blocked from receiving messages.  

    6/ Review Non-Delivery Reports (NDRs) 

    If you are receiving bounce-back messages, these reports can provide useful clues. 

    • Please any error messages they received. 
    • Common errors like 550 5.7.606 may indicate the sending IP is blocked. 
    • You can request removal via Delist IP - Delist IP 

    7/ Contact IT administrator:      

    Since their account is managed by their organization, please tell them to contact their IT administrator to review their permissions and policies. If the issue persists after these checks, ask their IT administrator to submit a support request directly to Microsoft Support team.          

    They can raise a support ticket by visiting: Get support - Microsoft 365 admin | Microsoft Learn    

    In case they do not know who is their IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support  

    As community moderators, we appreciate your understanding that our access to internal development details is limited. Our primary role is to guide users toward the appropriate resources and support channels. While we may not have visibility into deeper backend analysis, we’ll continue doing our best to support you within the scope of our responsibilities.         

    I hope this information is helpful. Please follow these steps and let me know if it works for you. If you have any updates regarding the issue, please feel free to share them with me.          

    Thank you for your patience and your understanding. I look forward to continuing the conversation. 

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have any 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?

  2. AI answer

    2026-05-08T20:46:16.6566667+00:00

    In Outlook on the web, messages can show as sent while still not arriving for some recipients. Use these checks and actions:

    1. Confirm the recipient side
    • Ask the recipient to check Junk/Spam and any mail rules or filters that might move or delete messages.
    • If the recipient uses a group address, verify that all group members’ addresses are valid and up to date. Remove any old or invalid addresses from the group if you manage it.
    1. Check for non-delivery reports (NDRs)
    • If any of the “delivered” messages later generate a delivery failure or bounce message, review the error text.
    • Common causes include:
      • Invalid email address
      • Recipient mailbox full
      • Recipient mail server issues
      • Spam filters blocking the message
    • For Outlook.com accounts, see the specific error in the NDR and apply the suggested fix. For example:
      • Errors mentioning “blocked” or “listed in” (spamcop, dynablock, blackhole, spamhaus) mean the recipient’s server is blocking the sending server as suspected spam. In that case, the recipient’s email provider support must unblock the account or domain.
    1. If using Outlook.com as the sending account
    • Review the article on “Sent email in Outlook.com comes back ‘delivery failed’” and match the error text from any NDRs to the documented causes and fixes.
    • If messages are not generating NDRs but still not arriving, the recipient’s spam or security filters are the most likely cause; ask them to add the sender address/domain to their safe senders list and to work with their mail admin.
    1. When no error is returned
    • If the message stays in Sent Items with no bounce and the recipient still does not see it, the issue is almost always on the recipient’s system (filters, quarantine, or security gateway). The recipient’s mail administrator should trace the message on their side.

    References:

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

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.