I can't install any program

Hello, I've been using this page for a long time and this never happened to me. I'm trying to install a program (Sketch 48.2) and when I try to open it, it doesn't seem to open correctly. Instead, it creates the typical TNT disk image on the desktop but the name of that disk image is "AnyTrans for Android 6.3.3", which is also a program that I got from this page, used without problems and that I recently uninstalled because I didn't need it anymore. When I click the Sketch 48.2 icon in the Finder's sidebar, a message saying: "Sketch 48.2 cannot be opened because the original item can not be found" appears. I have no clue of what is happening and how can I solve it. I would appreciate your help since I use this webpage a lot.
Thank you for your help!

Hello, Remove any version of sketch and any trans from your Mac using cleanmymac. Download Sketch again from this link:https://appdrop.net/ofcwsjbq72z3

mount the dmg and then double click the folder "Manual Install" (inside will be another dmg)
mount that dmg then you will see the sketch icon and drag it to the Applications folder wait for it to copy and then navigate to your Applications folder and open Sketch.app

Hope this helps