It sounds as though you need to confirm the settings of your collisions:
- The default response of your ‘Projectile’ channel; for simplicity, this shouldn’t be set to ‘Ignore’
- The collision response of the object you’re trying to land a trace on; likewise, this shouldn’t be ‘Ignore’
- Whether you’re using a Line Trace or Multi Line Trace; if you’re using Multi Line, the logic is counter intuitive. See the following post:
Multi Line Trace Confusion - Programming & Scripting / Blueprint - Epic Developer Community Forums