Recently I noticed that the "It's not SPAM" button doesn't work when I'm in any shared mailbox.
This is only true for OWA. If try to do it from Outlook Desktop, it works.
I managed to replicate the issue in Chrome, Edge and IE (haven't tried with other browsers).
It this behavior normal and if not, is there anything I can do to fix that?
Open a support ticket and report the issue, so that the corresponding team can update the add-in.