In February 2016, a colleague (a prominent logician) at the University of Bristol’s Philosophy Department invited me to speak at a conference on logic and truth theories in June 2016. (I am a logician and that is my area of expertise.) The conference website at Bristol has, oddly, been deleted. But an MCMP listing for the conference is here.
Two months later, after the speakers had been announced in his department, two Philosophy professors there demanded that I be uninvited. The embarrassed organizer then told me about it and we knew there was little we could do to stop these blacklisters.