Exchange Online: We've detected an increase in email message rejections from multiple

[Jobos]

So as title really. We use 365 for email and had this warning appear today. We are only using spf as never got round to setting up dkim or dmarc. Does the warning mean spam is being sent to appear coming from our domain and would configuring dkim or dmarc stop the warning?

 

The spf we are using is v=spf1 include:spf.protection.outlook.com ~all

 

Thanks in advance.

[Guest Guest]

I’ve had the same notification, had a look in NCSC mail check and we’ve had six refused in the last week or so

[andy_b]

Seems to be a generic message, we have it too.

 

Action needed

If your sending domain is configured with email authentication records like SPF, DKIM,DMARC in DNS and you're not sending a large rate or volume of emails that exceeds the sending limits of the service, you're not impacted and there is no action required by your organization.

 

We have SPF, DKIM, DMARC, MTA-STS and have seen no impact, so nothing to do.

 

I would look at getting these setup tbh.

[Jobos]

I’ve had the same notification, had a look in NCSC mail check and we’ve had six refused in the last week or so

 

We just signed up with NCSC and it's saying no dmarc found which I already knew so that will be a job for next week.

[andy_b]

I’ve had the same notification, had a look in NCSC mail check and we’ve had six refused in the last week or so

 

8 for us this week - fairly typical week. There does seem to be a massive amount of .onmicrosoft.com spam the last few days, maybe that has triggered something.

[chaplic]

me too, in a commercial tenant. Not seen in my own tenant, school tenant, or a dev tenant I have. Maybe just sent to all tenants with users>x or allow SMTP relay etc.