byb mails being triggered, how to know from where its is coming from

Summary:

Content (please ensure you mask any confidential information):

Hello,

We get this byob mails on some days, comes from a do not reply email so wanted to check from whee are they being triggeed.

Any idea how do we check that ?

Version (include the version you are using, if applicable):

24b

Code Snippet (add any code snippets that support your topic, if applicable):