A virtual event with Fed Governor Christopher Waller was canceled on Thursday after the Zoom videoconference was “hijacked” by a participant who displayed pornographic images that was visible to all viewers.

Waller had planned to deliver remarks (his prepared hawkish speech is here, a Reuters summary can be found here) on the economic outlook to the Mid-Size Bank Coalition of America, which was hosting the event, but it was not meant to be.

“We were a victim of a teleconference or Zoom hijacking and we are trying to understand what we need to do going forward to prevent this from ever happening again. It is an incident we deeply regret,” said Brent Tjarks, executive director of the Mid-Size Bank Coalition of America (MBCA), which hosted the event via a Zoom link. “We have had various programs and this is something that we have never had happen to us.”

Tjarks said that he suspects one of the security switches that mutes those watching an event was set incorrectly, but he was not yet sure of the details.

A few minutes before the event was to start, one participant using the screen name “Dan” began displaying graphic, pornographic images, according to a Reuters reporter on the call.

Microphones and video were not muted by the organizer upon joining, and more than 220 participants on the Zoom call at one point before it was terminated,

The decision to cancel was made in consultation with the Fed after the intrusion. After releasing Waller’s prepared remarks, the Fed said in a statement that “there are technical difficulties with Governor Waller’s virtual event and it has been canceled.”

The Fed said the event, which was to feature a speech by Waller as well as a question-and-answer session, was canceled due to “technical difficulties.”

Fed events are typically highly choreographed and security is usually tight.