Greetings.
My organization experiences a strange issue regarding the Non-Delivery-Report (NDR) messages that are created by Microsoft Exchange Online and this problem oc… (läs mer)
Greetings.
My organization experiences a strange issue regarding the Non-Delivery-Report (NDR) messages that are created by Microsoft Exchange Online and this problem occurs only when we use Mozilla Thunderbird and only with my organization's domain (to which i am an admin). When we send an email to a non-existent email address, the NDR generated by Exchange is delivered to junk folder. I have already contacted Microsoft support, but since the problem does not occur when i use their products, they directed me to contact Thunderbird support instead.
No filters or rules have been set within the Thunderbird client. In fact, if i send the message and close Thunderbird before the NDR is received and then open another email client (e.g. Outlook in desktop or online), the NDR is still delivered in my junk folder, so it seems that the filtering is done in the server.
To my best judgement, since the message that is marked as junk is not the one that was generated and sent through Thunderbird but the one that the server informs me that the recipient's address does not exist, it seems to me that it is a server-side problem. Moreover, it seems to me that in this case Microsoft marks its own system-generated messages as junk which sounds a bit strange. However, Microsoft's support directed me to Thunderbird support so here we are.
Any help would be greatly appreciated. Feel free to ask me for any additional information that might be needed.
Thanks in advance.