I set up a workflow that sends a Marketing email to a contact. It is followed by a condition that checks wether a contact replies to the email.
The thing is that we tried it with some of our colleagues, and after replying to the email, the contact stayed stuck at the step where it checks for replies. Even in the CRM, on the contact page, we can clearly see the Marketing email sent as well as the number of times it was opened, but it did not detect any of the replies we made to it.