Account blocked from receiving mail ? unknown or illegal alias?

Occasional Visitor
I am in the process of moving a small office from a local ISP (call them "" ) who had been providing connectivity, email, and web hosting. We have moved to a different large national (Canadian) ISP for connectivity (call them ""), but moved our email to Office 365 Business and our web hosting to a local web hosting provider.
Email seems to be working for the most part. Messages sent to do get delivered to the mailboxes and people can sign into to see them. We ran for a while without changing our mx records away from and having mail being forwarded from on a per-mailbox basis to, but now our mx records point properly to microsoft and is out of the picture as far as email is concerned.
Here is the problem. We have a printer/scanner in the office which is set to use for outgoing email. This seems to be working to deliver scanned documents to everyone with pretty much any email address:,, and even which is hosted by Office 365. However when we send to we get nothing. With the return address of the scanner set as deliveries to do not get through, but all other deliveries do. Withe the return address of the scanner set as again deliveries to do not get through, but all other deliveries do, but the gets an error message sent by the machine saying either:
Diagnostic-Code: smtp; 5.1.0 - Unknown address error 550-'4.2.1 "Account blocked from receiving mail ":' (delivery attempts: 0)
Diagnostic-Code: smtp; 5.1.0 - Unknown address error 550-'5.1.1 unknown or illegal alias:' (delivery attempts: 0)
Note, this is not using the info on setting up a fax/scanner/etc to send using the Microsoft servers as detailed here:
In this case we are using the server to send the message.
Does anyone have any idea why I am getting these rejection notices? Why does one address get 4.2.1 "Account blocked from receiving mail" and the other gets  5.1.1 unknown or illegal alias?


1 Reply


One answer would be to get an Exchange Online mailbox for your copier and set that mailbox username address and password on the copier.


I looked at this as an option but we didn't want the extra cost as we are a small business.  We now use a shared mailbox email address and staff have to email themselves the attachment and then send it from Outlook to external recipients.