It's not clear what led to the problem, although SpaceX said the parachutes weren't responsible.
The crewed demo mission is still officially expected in May. However, Parabolic Arc sources said that the failure along with separate preparation issues made it "likely" that the flight would wait until June. It wouldn't be surprising if the COVID-19 pandemic complicated the situation, for that matter.
The failure compounds problems NASA has had getting viable private crew capsules into service. On top of SpaceX's challenges, Boeing's botched Starliner test flight is introducing setbacks. It could be a while before US rockets and capsules are once again ferrying astronauts into orbit, as eager as the US might be to reinvigorate its space program.