Okay so I think I have found the issue for people trying to work with 1.16.5 forage. Whenever you download the file and extract it to your minecraft, it no longer had the jar file. I was going through my forage for 1.17 and when you look at the files that it downloads it extracts a .jar file. 1.16.5 however is no longer doing this. This is an issue with the file not your computer. I don't know how to get this issue fixed for if someone knows how. It would be greatly appeciated if someone knew how to fix this.