Hello,
If sender received a bounce email, I need to know what it says.. your post only provided a small piece of information, which is not enough to form a conclusion.
Also, what's sender's sending domain? For example, @business.com?
Not receiving emails from some safe senders/contacts
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laura m
0
Reputation points
Sender receives message with SN1PEPF0002636B.mail.protection.outlook.com (10.167.241.136) with Microsoft
Outlook | Web | Outlook.com | Email
3 answers
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EmilyS726 223K Reputation points Independent Advisor2026-03-17T20:50:49.2933333+00:00 -
laura m 0 Reputation points
2026-03-17T21:32:20.0033333+00:00 Emails are from contacts and also from trusted companies.
The sender receives the following:
SN1PEPF0002636.MAIL.PROTECTION.OUTLOOK.COM rejected your message to ******@hotmail.com
Your message wasn't delivered because the recipients email provider rejected it.
Sending domaim does not pass dmarc verification
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EmilyS726 223K Reputation points Independent Advisor
2026-03-17T21:36:28.78+00:00 The key message here is "Sending domaim does not pass dmarc verification" So I take it that this is a business sender?
These days, SPF,DKIM and DMARC records are mandated in the email industry. Wrong or missing configurations can lead to their emails being rejected on the server level.
This is not something you can fix. Let your contact know, so they can inform their IT. Their DMARC record must be corrected. Once corrected, their emails would be accepted in 24 - 48 hours, because DNS record sometimes can take that long to propogate on their end.
Feel free to share this article with them regarding Microsoft's requirement. https://techcommunity.microsoft.com/blog/microsoftdefenderforoffice365blog/strengthening-email-ecosystem-outlook%E2%80%99s-new-requirements-for-high%E2%80%90volume-senders/4399730
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laura m 0 Reputation points
2026-03-17T22:03:55.1+00:00 It is both personal and business senders. They can send the same email to other hotmail.com addresses.
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EmilyS726 223K Reputation points Independent Advisor
2026-03-17T22:09:00.19+00:00 If a personal sender also cannot send you emails, I need to know if they receive any bounce back? Without that information, it would be quite challenging to pinpoint the reason.
As for why some business can send to other hotmail.com address, the answer really depends.
These days, a single email address or domain is often used by several different sending services, which is very common for businesses. I am IT for my organization, and we have multiple services authorized to send on our behalf. For example, Salesforce sends sales follow-up emails, Constant Contact sends newsletters, Square sends invoices and receipts, and Microsoft handles our main email service.
When a business allows third-party services to send email using its domain, having correct SPF/DKIM/DMARC correctly set up is extremely important. For example, if I only set them up for Salesforce and Constant Contact but forget to include Square, then any receipt sent from Square could be rejected by receiving email server.
From the recipient’s side, there is no obvious difference because every message still appears to come from
@business.com. That is why people often describe it as “some emails arrive, some don’t,” when in reality the messages are being sent from different services and one of them is not properly authorized.
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laura m 0 Reputation points
2026-03-17T20:18:59.23+00:00 I had already done all of the suggestions which did not resolve the problem
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Q&A Assist2026-03-17T20:17:12.98+00:00 AI generated content. This question contains an answer created with AI from Q&A Assist. Learn moreFollow these steps to troubleshoot not receiving mail from some safe senders/contacts in Outlook.com / Outlook on the web:
- Confirm the sender is not blocked
- Sign in to Outlook.com or Outlook on the web.
- Select Settings > Options or Mail.
- In the left pane, select Blocked Senders or Block and allow.
- If the sender’s address or their domain (for example,
@example.com) appears in the Blocked senders list, select it and remove it.
- Verify Safe Senders configuration
- In Outlook on the web options, go to Junk Email or Block and allow.
- Under Safe senders list, make sure the sender’s exact email address or their domain is added as a safe sender.
- To add: type the email address or domain in the text box under Safe Senders List and select Add.
- Optionally ensure Also trust email from my Contacts is selected so messages from contacts are treated as safe.
- Check Outlook desktop Junk Email settings (if using Outlook client)
- In Outlook desktop, on the Home tab, select Junk > Junk E-mail Options.
- On the Safe Senders tab, verify the sender or domain is listed; if not, select Add, enter the address or domain, and select OK.
- On the Blocked Senders tab, remove the sender/domain if present.
- If messages are still missing
- Check the Junk Email folder and any custom folders/rules that might be moving messages.
- If the sender is in Microsoft 365 and still cannot deliver to the mailbox, they should verify their mail flow and any throttling or protection issues on their side using Microsoft 365 mail flow troubleshooting guidance.
- If the problem persists
- Use Outlook.com in-product help to contact support:
- In Outlook.com, select Help on the menu bar and enter the issue.
- If self-help does not resolve it, scroll to Still need help? and choose Yes to reach support.
- Use Outlook.com in-product help to contact support:
References:
- Confirm the sender is not blocked