Old Alias creating errors and cannot be created on new email system (zoho)

Question

Hi there. I am an officer 365 user but we no longer use Outlook and the email system. We use Zoho Mail as our email system now (since July 2019.

We did have a number alias setup with office 365 mail and they were deleted from the Office 365 admin panel. When I choose to re-use these aliases (we use them in many oages of our website and social accounts) the sender gets an email bounce error:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. See below the line.

Also, When trying to create the alias in Zoho mail we receive an instant message:

The email address is already registered with another account which is not a part of this organization.

When I research the internet there are threads that tell me the alias needs to be deleted from the backend (wrong term) as they remain there until deleted.

Can you help?

---

******@inxxxxxoks.com, ERROR CODE :550 -

550 5.0.0 Invalid Recipients.

Reporting-MTA: dns; mx.zohomail.com

Arrival-Date: Thu, 17 Dec 2020 15:02:16 -0700

Original-Recipient: rfc822; ******@ixxxxxks.com

Final-Recipient: rfc822; ******@ixxxxxxoks.com

Status: 550

Action: failed

Last-Attempt-Date: 17 Dec 2020 22:02:49 GMT

Diagnostic-Code:

550 5.0.0 Invalid Recipients.

Received:from mail.zoho.com by mx.zohomail.com

    with SMTP id 16082xxxxxxxx8.7829176458034; Thu, 17 Dec 2020 14:02:16 -0800 (PST)

Message-ID:<******@inxxxxxoks.com>

Date:Thu, 17 Dec 2020 15:02:16 -0700

From:John Wagner-Stafford <******@ixxxxks.com>

To:"hello" <******@inxxxxxks.com>

Subject:Where is this bouncing from.

Content-Type:multipart/alternative;

    boundary="----=_Part_1864514_914017225.16xxxxxx36388"

User-Agent:Zoho Mail

<Modified by moderator due to privacy>

Answer 1

Hi John,

Thank you for providing the detailed error message. When you say “I am an office 365 user but we no longer use Outlook and the email system”, since you are not using Exchange online service, may I double confirm whether you had removed your custom domain from Office 365 Business subscription? See Remove a domain

Does this issue happen with every creating alias or specific alias?

Please provide us with the detailed information about Office 365 business subscription which you were using and tenant domain (e.g. @contoso.onmicrosoft.com) via the private message further analysis.

Moreover, may I know whether you get a chance to report it to Zoho support? If not, I would suggest please contacting them and see what they say. If they point out something on our side, please let us know.

I have sent you private message and here is the link to access it: https://answers.microsoft.com/en-us/privatemessages/list

Your patience and cooperation will be highly appreciated. Have a nice day and stay safe!

Best regards,

Shyamal