Ok I see may bad, the issue is that Convert Mouse location to world give you the location of the mouse next to the camera so you need to do 2 traces here, one to get the location the first object under the mouse cursor and the second one from the character to the impact point.
You may want to do some refining of the result of the first trace for example to offset it from the ground, check if the result is in valid (if the player is clicking somewhere where you dont want him to attack you could decide to block it) …
Edit : You can check https://youtu.be/b1_efR9hrT4 for detailed information about the node (his video are old but I started with that long ago and I can tell you they are greats