alt Hacker NewsThey're referring to the bounced notification message, not the fact that the mail bounced. Verb and noun.
A 5xx is a bounce, and results in a bounced email message. Variances always abound, but I'll stick with my 30 year old terminology, and it is correct.
That's fair with regards to your statement, but "doubled112" assigned the agency to Microsoft, saying that "Microsoft bounces" their traffic, which is demonstrably not what is happening.