Billboard posted this statement released by the organizers:
“It’s a dream for agencies to work with iconic brands and to be associated with meaningful movements. We have a strong history of producing experiences that bring people together around common interests and causes which is why we chose to be a part of the Woodstock 50th Anniversary Festival. But despite our tremendous investment of time, effort and commitment, we don’t believe the production of the festival can be executed as an event worthy of the Woodstock Brand name while also ensuring the health and safety of the artists, partners and attendees."
Although there are still conflicting reports as to whether it is truly cancelled
"Woodstock 50 vehemently denies the festival's cancellation and legal remedy will (be) sought,"