Incorrect blocking of an email sender

Question

Incorrect blocking of an email sender

Bob D'cruz 0

Hi,

I have an email contact that has all their emails to me bounce with a reason given that I have marked them as spam.

I have added them to safe senders and checked that I have not blocked them but I still do not get their emails. They are in my contacts. Note: the email is not visible in online inbox or the outlook client.

On their side it seems that their CRM system handles the emails so they do not see the details of what is sent back. No error messages available etc.

I need to find a way to ensure that their emails get through to me. It is worth noting I have had the same issue in the past with 2 other senders, in all 3 cases they are companies, perhaps there is a common element here, perhaps they all use the same CRM system, I don't know.

My email is address is a hotmail.com one, not outlook.

Thanks

Bob

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Answer 1

EmilyS726 266.8K Independent Advisor

Bob,

Since the other sender is sending it via CRM, I am almost certain that they didn't have SPF, DKIM set up in the CRM to send email on their domain address's behalf.

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 (our CRM) 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, all of those services must be included in the SPF record in DNS and have DKIM set up correctly too. For example, if I include Salesforce and Constant Contact in SPF but forget to include Square, then any receipt sent from Square could be rejected because SPF would fail. 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.

You would need to have your contact check with their Email admin/IT, have them review these records on their end. Microsoft will either flag their incoming emails as spam, or reject them entirely if these records are missing or wrong. And this is something that needs to be fixed on their end.

Bob D'cruz 0 Reputation points

2026-09-16T13:15:24.49+00:00

Thanks for that, not sure how much I can do with the senders side of things, I have asked.
Bob D'cruz 0 Reputation points

2026-09-16T13:21:18.5533333+00:00

Thanks for that, not sure how much I can do with the senders side of things, I have asked.
EmilyS726 266.8K Reputation points Independent Advisor

2026-09-16T13:28:18.7533333+00:00

Make sure you ask them to escalate to their email admin/IT department. For CRM front line users, they may not necessarily understand the backend of configuration, so they might simply go by whether the email was sent.