505 error sending and receiving

[#1]

I have intermittent problems both sending and receiving plus.net emails. 

Example 1 receiving. 
A contact that has been corresponding with me for many years using the same email address sometimes gets an email returned with the following error:

"550 5.4.355 Remote server returned recipient domain does not exist -> 550 #5.1.8 Domain of sender address <xxx@xxx.com> does not exist
Message rejected by:     avasin-ptp-001.plus.net".

Example 2 sending.
I have been sending emails to another contact for many years using the same email address. Recently they are re rejected with the following error message:

"Delivery to the following recipients failed permanently:

   * yyy@outlook.com

Reason: A message that you sent to the following recipient could not be delivered due to a permanent error. ** The remote server ?? responded with: ** yyy@outlook.com ??:?? This message was created automatically by mail delivery software on the server .

Final-recipient: rfc822; yyy@outlook.com
Diagnostic-Code: smtp; 550 5.7.515 Access denied, sending domain MYDOMAIN.PLUS.COM doesn't meet the required authentication level. The sender's domain in the 5322.From address doesn't meet the authentication requirements defined for the sender. To learn how to fix this see: https://go.microsoft.com/fwlink/p/?linkid=2319303 Spf= Pass , Dkim= Fail , DMARC= Pass [VI6PPF0ECF518A5.EURP195.PROD.OUTLOOK.COM 2025-08-20T10:59:02.470Z 08DDDC65A24993BD] [SJ0PR13CA0220.namprd13.prod.outlook.com 2025-08-20T10:59:02.513Z 08DDDF961C8A6FE0] [SJ5PEPF00000205.namprd05.prod.outlook.com 2025-08-20T10:59:02.559Z 08DDDFD79747929B]"

Any suggestions how to correct this?

[#2]

@MGBRoadstar 

Example 1

Unless you have your own domain xxx.com hosted by Plusnet then the mail should be addressed to xxx@<youraccountname>.plus.com

Example 2 has/is being discussed at length here https://community.plus.net/t5/Email/From-address-doesn-t-meet-the-authentication-requirements/td-p/2...

[#3]

Example 1 arises from a misconfigured email client, alternative sender identity or send on behalf of sender address.

Or if your own domain - has it expired?

[#4]

Hi,

For Example 1:

My domain is hosted by PlusNet and the email was addressed to me@mydomain.plus.com

This sender has used this email address for many years without problems, and it has only recently started happening intermittently.

I haven't made any alterations to my email client configuration .

I don't know what an "alternative sender identity or send on behalf of sender address" is. Again this only started happening recently and it is intermittent.

My domain hasn't expired.

[#5]

@MGBRoadstar 

My domain is hosted by PlusNet and the email was addressed to me@mydomain.plus.com

Thanks, that wasn't clear from your initial post.

A contact that has been corresponding with me for many years using the same email address sometimes gets an email returned with the following error:

If the problem is intermittent then that would point to a temporary DNS lookup problem, either the Plusnet DNS servers ro the sending email server. If it was the former I'm sure the forum would be littered with similar problems, which there doesnt seem to be.

[#6]

---

@MGBRoadstar wrote:

I have intermittent problems both sending and receiving plus.net emails. 

Example 1 receiving. 
A contact that has been corresponding with me for many years using the same email address sometimes gets an email returned with the following error:

"550 5.4.355 Remote server returned recipient domain does not exist -> 550 #5.1.8 Domain of sender address <xxx@xxx.com> does not exist
Message rejected by:     avasin-ptp-001.plus.net".

@MGBRoadstar wrote:

My domain is hosted by PlusNet and the email was addressed to me@mydomain.plus.com

This sender has used this email address for many years without problems, and it has only recently started happening intermittently.

I haven't made any alterations to my email client configuration .

---

As @MisterW suggests there was clarity lacking in the original post...

Where does the error message come from?  Some message they sent to use reporting the bounce back message THEY received from Plusnet?

Do they ALWAYS select your email address from a contacts list or do they sometimes type it in ... and get it wrong?

If this is the message THEY received from Plusnet then "remote", "recipient" and "sender" need to be understood as from then to you, not the other way around as I did initially.  Too much redacting can mask the problem you are seeking assistance with.  If email addresses are typed, then there is a significant opportunity for them to be mistyped.

[#7]

Hi @Townman,

In Example 1 this is the error message that the sender receives when they send an email to me.


The sender always uses either a contact list or a group email with my email address as one of the group. Both can get bounced back, but not every time. They never type my address in.