Our company recently upgraded to Outlook 2016 (not 365). I'm testing a newsletter which will be sent internally as well to our external clients. The message includes an 'unsubscribe' link at the top (not my own, this is a function of Outlook) and the text when I review that link reads as follows:
"It looks like this is a newsletter, but we aren't sure if it is safe to unsubscribe from it using the information provided by the sender. If you don't want to receive from this sender again, you can block it."
Does anyone have any information on why Outlook does not trust my unsubscribe? In this case, I'm using the default unsubscribe with a Marketo template I've updated code on, the unsubscribe is not hand-coded in my email.