Change value to App.config file

I am trying to change the value of the App.config file and it does not save anything to me, I do not get any errors when saving, and when it rerun the program continues with the same value.

var configFile = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
var settings = configFile.AppSettings.Settings;

Console.WriteLine(settings["id_shops"].Value = "50");

configFile.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection(configFile.AppSettings.SectionInformation.Name);