AOL and YAHOO emails undeliverable from Office365

Occasional Visitor

sending to aol & yahoo are kicking back. Anyone else getting this issue?


this is the message:

our message to - couldn't be delivered.
When Office 365 tried to send your message, the receiving email server outside Office 365 reported an error.

How to Fix It
Check the "Reported Error" from the "Error Details" section shown below for more information about the problem. The error might tell you what went wrong and how to fix it. For example, if the error states that the message was blocked due to a potential virus or because the message was too large, try sending the message again without attachments.
If you're not able to fix the problem, it's likely that only the recipient's email admin can fix it. Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin about the problem. Give them the "Reported Error" from the "Error Details" section below.

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More Info for Email AdminsStatus code: 550 5.0.350 

The error reported by the receiving server wasn't specific enough to determine the exact nature of the problem. These errors often indicate the message violates a security or policy setting configured on the recipient's email servers.

If the sender is unable to fix the problem by modifying their message, then it's likely a problem that only the recipient's email admin can fix. Try the following:

Check the error for information about the problem - The "Reported Error" returned by the external email server can be found in the "Error Details" section below. This error might tell you what went wrong and provide clues for how to fix it. For example, if the error states the message was rejected due a Sender Policy Framework (SPF) issue, then you'll have to work with your domain registrar to correctly configure your domain's SPF records.

Check the error for information about where the problem is happening - For example, look for a domain name like A domain name in the error might suggest who is responsible for the error. It could be the recipient's email server, or it could be a third-party service that your organization or the recipient's organization is using to process or filter email messages.

If you can't fix the problem, contact the responsible party's email admin - Give them the error code and error message from this non-delivery report (NDR) to help them troubleshoot the issue. For security or policy violation issues, it might be sufficient for them to just add your sending IP addresses or domain to their allowed senders list.

It's likely that only the recipient's email admin can fix the problem. Unfortunately, it's unlikely Office 365 Support will be able to help with these kinds of externally reported errors.

Original Message Details

Created Date:10/2/2020 2:07:28 PM
Sender Address:-
Recipient Address:-

Error Details

Reported error:550 5.0.350 Remote server returned an error -> 554 Message not allowed - [PH01] Email not accepted for policy reasons. Please visit
DSN generated
1 Reply

@peterlVD I have two clients who have been getting these over the last few days. from Yahoo and AOL email accounts. 

The error reported in both of their cases has been:

"237 temporarily deferred due to unexpected volume or user complaints"


It also refers to a link:

On this site, you can get some good information and also this link in order to set up a CFL(Complaint Feedback Loop) request for your domain which will allow you to get notifications when your domain's emails get flagged as spam. 

Yahoo CFL request: Yahoo! Help - Submit a Form


Note: the CFL setup will send an authentication code to "Postmaster@" for the domain you are requesting the CFL for so have that configured prior to attempting to submit this form.