Not a signed unity app error?

when i want to locate my installed unity editor to unity Hub, after selecting the unity.exe it shows “not a signed unity app” and then nothing’s gonna happen. what does that mean? i also logged into hub but this was not the solution too.
Any help?
hub version: 2.4.2
Unity version: 2020.2.7f

I faced the same problem with the current latest version.
Here’s an easy solution.
Keep Unity Hub running and navigate to the file you have the Unity setup installed. And run the unity.exe file, it should automatically add the unity editor in the unity hub and open the editor. Don’t forget to exit the editor.