Dotnet: System.FormatException: Unsupported JSON token 'EndObject' was found. Path '', line 13 position 1


I try to use Radzen but when i run the application i got this:

radzen: Generating code …
radzen: Code generation done in 221ms.
dotnet: Restoring packages …
dotnet: Restore completed in 282,72 ms for C:\Users\Marden\Desktop\RadzenCep\server\project.csproj.

dotnet: Usando as configura??es de inicializa??o de C:\Users\Marden\Desktop\RadzenCep\server\Properties\launchSettings.json…


dotnet: Unhandled Exception:
dotnet: System.FormatException: Unsupported JSON token ‘EndObject’ was found. Path ‘’, line 13 position 1.
at Microsoft.Extensions.Configuration.FileConfigurationProvider.Load(Boolean reload)
at Microsoft.Extensions.Configuration.FileConfigurationProvider.Load()
at Microsoft.Extensions.Configuration.ConfigurationRoot…ctor(IList`1 providers)
at Microsoft.Extensions.Configuration.ConfigurationBuilder.Build()
at Microsoft.AspNetCore.Hosting.WebHostBuilder.BuildCommonServices(AggregateException& hostingStartupErrors)
at Microsoft.AspNetCore.Hosting.WebHostBuilder.Build()
at Cep.Program.BuildWebHost(String[] args) in C:\Users\Marden\Desktop\RadzenCep\server\Program.cs:line 16
at Cep.Program.Main(String[] args) in C:\Users\Marden\Desktop\RadzenCep\server\Program.cs:line 10

It seems that Radzen has created invalid launchSettings.json file. Can you please attach that file here so we can take a look?

The site does not permit me to upload files, here is the content of file:

“profiles”: {
“project”: {
“commandName”: “Project”,
“launchBrowser”: true,
“environmentVariables”: {
“applicationUrl”: “http://localhost:64117/

That file looks valid from first sight. Can you zip the whole ‘server’ directory of your Radzen application and send it over to We will run it locally and see where the invalid JSON file is.

Best regards,

you can download from my google drive

Thanks! The problem is in the appsettings.json file. Unfortunately it is a bug with persisting the connection string when a data source has underscore in its name. As a workaround you can delete the existing Snak_CEP data source and create a new one called SnakCep.

We will fix that problem and release a hotfix build tomorrow.

Hi Marden,

We’ve just published Radzen 1.33.2 with fix for this problem included.

Best Regards,

Hi @enchev, @korchev thank you, I will test.