Sophos email security - not show error XGEMAIL_0009

The 0009 Error is if the user blocked the sender.  Sophos Email: "550 5.7.1 XGEMAIL_xxxx Command Rejected" translated [Inbound emails] 

You dont want to show case this error to the sender?  

The 0009 Error is if the user blocked the sender.  Sophos Email: "550 5.7.1 XGEMAIL_xxxx Command Rejected" translated [Inbound emails] 

You dont want to show case this error to the sender?  

Exactly, so that the sender does not know that he is on a block list.

That is not configurable - May i ask the use case behind this? 
Did something happen? 
Because that is the first time, someone reach out about this. 

It is simply the request of a client of mine who states that in his old email management system he had the possibility to choose not to send any alerts to blocked senders.

Hi Maurizio Troilo 
You mean like a blackhole effect right? If so, then this would have to be a feature request as I do not see any options currently for this in the product.
A workaround/option I can think of for now would be to block the sender at the email client side not through the Sophos smartbanner/self service portal. This is dependent on the email client though if it will/will not notify the sender.

There is a current feature request. It is CEMA-I-288

To be able to add a vote to the request and/or to know its status in the future, please contact your Sophos account manager.