Bounce mail gets undedected

[vankampenp]

Maybe I am doing something wrong, but a clear bounce message is not recognized as such.
I am reading messages from a dedicated mailbox:
foreach (var uid in uids) {
var message = await inbox.GetMessageAsync (uid);
and than processing the message:
var result = BounceDetector.Detect(message);

This returns as not a bounce message for

Could not deliver message to the following recipient(s):

Failed Recipient: huhhup123124@gmail.com
Reason: Remote host said: 550 5.1.1 The email account that you tried to reach does not exist. Please try
5.1.1 double-checking the recipient's email address for typos or
5.1.1 unnecessary spaces. Learn more at
5.1.1 https://support.google.com/mail/?p=SuchUser 4-v6si5409935edh.451 - gsmtp