there was a 2d animated movie aired way back around maybe 2010 in cartoon network. i remember there being a witch villain, some good ghosts, and some guy and his friends as the protagonist lol. my uncle used to say it’s ghostbusters but i’m pretty sure it’s not
I am not sure with the info as Casper comes to mind with the ghosts but that is different type animation. There is also a few Scooby doo movies that were on CN like the witches ghost and several Ben 10 specials that maybe could fit the description?
I did find this list, I am not sure if it is comprehensive or not, but it shows the air date on the far right with the movie / special that aired on the left on CN. Maybe you can find it on this list? List of movies and specials aired on Cartoon Network – Nickandmore!