Routing to blackhole in cpanel not working

[koda]

I'm trying to temporarly overcome a backscatter attack, in the meanwhile I tried to set on this domain the default address in CPanel 76.0.20 to Discard (Not Recommended).
But I made a simple test, writing an email to a non existent address and I receive back a failure notice for 550 5.1.1 [email protected] User doesn't exist.
Shouldn't it work so that I receive no delivery report?

Thanks

 

[cPanelMichael]

Hello @koda,

Can you share the output from /var/log/exim_mainlog when reproducing the issue? Here's a command you can use to obtain this information:

exigrep MSGSUBJECT /var/log/exim_mainlog

Replace MSGSUBJECT with the subject of the test email you send (use something unique when testing). Ensure to replace real domain names and IP addresses with examples when pasting the output here.

Thank you.