Emails registered as sent but they are not being received

Question

I'm sending e.mails to assorted accounts, all of which are on my safe senders list. They show up in my Outlook sent column, but they are not being received. The recipients' in-boxes aren't full and my own address isn't on their spam lists. Help!

Answer 1

Dear @JA,

Thank you so much for contacting Microsoft Q&A Support. 

Based on your description, I understand that you are facing with emails show up in Outlook’s Sent folder but are not being received by the recipients, even though they are on the safe senders list, their inboxes aren’t full, and your email address are not blocked from their side. 

Therefore, I find several workarounds that may help you: 

1.You can try Outlook Web to send emails to check if it works because in some cases, emails sent via Outlook desktop app behave differently than those sent via Outlook Web. Webmail may bypass certain client-side issues.  

Reference: Emails shown in Sent, but not delivered to recipients | Microsoft Community Hub 

2.You and your recipients can use the Message Trace to check the message or email logs to see if the emails were rejected or delayed. So that you can know their delivery status.

References: Run a message trace and view the results in the Exchange admin center in Exchange Online | Microsoft Learn 

3.You should ask the recipients to check the quarantine portal or security dashboard because even if spam/junk folders were checked, some emails might be quarantined by Microsoft Defender for Office 365. 

You can consult in here: Find and release quarantined messages as a user - Microsoft Defender for Office 365 | Microsoft Learn

Also, ask them to check Spam Filter Settings: Recommend recipients set their spam filter to “Standard” instead of “Strict” and create inbox rules to route messages from the sender directly to the inbox. You can consult: Emails Not Coming Through Despite Safe Senders List - Microsoft Community  

4.You can also ask them to add your email address to Safe Senders List Properly to ensure you are added to the Safe Senders list in Outlook settings, not just in contact. 

5.Additionally, you should use tool to check your MX records to verify SPF, DKIM, and DMARC Records to ensure your domain has properly configured authentication records because misconfigured records can cause emails to be rejected or flagged as spam.  

6.You and your recipients should check again for the Transport rules in Microsoft 365 Exchange Admin Center. Mail flow rules that might redirect or delete emails. Also, check the Inbox Rules in Outlook, please click Settings icon > Mail > Rules to see if there are any rules may cause this issue.

I hope this information can help you to solve this issue. 

Wish you a pleasant day!

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Answer 2

Many thanks for your answers. Nothing worked though and it stopped of its own accord after a day or so. It's started up again though...