1.) Make sure you have the Able Ability Component on your preview character. Otherwise you get weirdness when trying to execute Abilities. You can also turn on Verbose for the Animation task and it’ll tell you whats going on under the hood. See if that pops up anything weird.
2.) That error is complaining that you have an Apply Damage Task, but you have either No Targeting logic on the Ability itself, or you don’t have a dependency defined for a query to populate who/what you’ll be applying damage to. If you have an query earlier on in the Ability, just add a dependency (Click on your Apply Damage Task, then right click on the query and click “add dependency”).