How to fix .dll file reference error in C#?

I was making a student reputation management app. I am developing it using MetroFramework and I got this error (in InitalizeComponents()). The error code is: System.IO.FileLoadException:'Cannot load file or assembly'MetroFramework, Version=1.4.0.0, Culture=neutral, PublicKeyToken=5f91a84759bf584a', or one of the files or assemblies that depend on it. The manifest definition of the found assembly and the assembly reference do not match. (Exception occurred HRESULT: 0x80131040)' All files: https://drive.google.com/drive/folders/1gDdtHbkkBrU_X_5tw3ft2nDk3K0InDZ-?usp=sharing