Account blocked from receiving mail ? unknown or illegal alias?

Copper Contributor
I am in the process of moving a small office from a local ISP (call them "Local-ISP.com" ) who had been providing connectivity, email, and web hosting. We have moved to a different large national (Canadian) ISP for connectivity (call them "nat-ISP.ca"), 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 someone@our-office.com do get delivered to the mailboxes and people can sign into http://offic.com/ to see them. We ran for a while without changing our mx records away from Local-ISP.com and having mail being forwarded from Local-ISP.com on a per-mailbox basis to someone@our-office.onmicrosoft.com, but now our mx records point properly to microsoft and Local-ISP.com 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 smtp.nat-ISP.ca for outgoing email. This seems to be working to deliver scanned documents to everyone with pretty much any email address: gmail.com, icloud.com, outlook.com and even other-company.com which is hosted by Office 365. However when we send to anyone@our-office.com we get nothing. With the return address of the scanner set as someone@our-office.com deliveries to anyone@our-office.com do not get through, but all other deliveries do. Withe the return address of the scanner set as someone@somewhere-else.com again deliveries to anyone@our-office.com do not get through, but all other deliveries do, but the someone@somewhere-else.com gets an error message sent by the smtp.nat-ISP.ca machine saying either:
 
Diagnostic-Code: smtp; 5.1.0 - Unknown address error 550-'4.2.1 "Account blocked from receiving mail ": someone@our-office.com' (delivery attempts: 0)
 
or
 
Diagnostic-Code: smtp; 5.1.0 - Unknown address error 550-'5.1.1 unknown or illegal alias: someone-else@our-office.com' (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 smtp.nat-ISP.ca 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

@j-beda 

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.