Could not load file or assembly System.Security.Permissions, Version=4.0.3.0

[4do4]

Hello!

I have next code on C#:

string SqlConnection = $"SERVER={sql.Host};PASSWORD={sql.Password}; UID={sql.Username};DATABASE={sql.Database}";
conn = new MySqlConnection(SqlConnection);
conn.Open();

after launching it returns an error: System.IO.FileNotFoundException: "Could not load file or assembly 'System.Security.Permissions, Version=4.0.3.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.

I put the necessary dll in almost all the server folders

I'm panicking!

.NET Core version 3.1

Already 4 hours can not solve the problem, please help

Thanks you all!

 

Edited May 13, 2020 by 4do4

[AxE]

You are missing a dll or have a wrong library loaded ... try unloading re-adding needed libraries.