Stop read receipts for shared mailbox

[gjvdkamp]

Hi all, 

We have Office 365 and set up a shared mailbox 'info'. Every day I get a few spam mails, but they always come in pairs. The first mail is a 'bla bla XLConnect Inquiry' (apparently that is still effectve to pass by spam filters) and then an 'Undeliverable bla bla XLConnect Inquiry' from the mail server of that non existing spam address. 

I get the feeling Exchnage is sending read receipts or smth for these emails. How can I stop it from doing that for a Office 365 Shared Mailbox? 

I tried logging in as that address, but it doesn't show any apps (so also not Outlook) b/c it is not a user, it's a shared mailbox.. 

Been through all the settings I can find but can't find anything that could stop these replies form being sent. 

TIA, GJ

[#2]

Hi!
Are you able to trace those outgoing messages from the shared mailbox?
Why not simply block the spammer?
You could also stop that with a transport rule.
May makes sense to check the AutoReply configuration for that shared mailbox as well:

Get-MailboxAutoReplyConfiguration <shared mailbox email address>