Value cannot be null (Parameter 'connectionString') .NET 6

I use .Net 6 and when I want to run my first migration, I get this error:

Value cannot be null. (Parameter ‘connectionString’)

My appsettings.json:

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=Solardb;integrated security=SSPI"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },

  "AllowedHosts": "*"
}

And this is my Configuration method in program.cs:

builder.Services.AddDbContext<SolarDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("ConnectionStrings")));

>Solution :

You don’t need to get the whole section. GetConnectionString does it already. You just need to put the name of connection string

builder.Services.AddDbContext<SolarDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));