The Dash blockchain stalled during the activation of its Dash Core v19 hard fork, chief technical officer Samuel Westrich announced by tweet on the morning of May 21. Developers announced a v19.1.0 fix about 13 hours afterward.
“It is important to realize that blocks and transactions on the Dash network that are not ChainLocked and not InstantSend locked should not be assumed to have true finality,” Dash developers warned while the chain was down. ChainLocked and InstantSend are security features unique to Dash.