Telerik Web Reporting undefined isVaild Error

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.NET Core .NET Framework Rendering Report Designer - Web
Trish
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Trish asked on 04 Feb 2026, 02:10 AM | edited on 08 Feb 2026, 08:09 PM

Hi 

I am using Telerik web reporting, and its givingan undefined isValid error on my web reporting designer.

 

Using Asp.net core, c# with front end react application

.NET SDK: Version:           9.0.304

React 18

Also getting this confgration errror from => http://localhost:{port}/api/reportdesigner/configuration

{

    "message": "An error has occurred.",
    "exceptionMessage": "Method 'CLIMessage' in type 'RuntimeInvalidLicenseStatus' from assembly 'Telerik.Reporting, Version=19.1.25.521, Culture=neutral, PublicKeyToken=a9d7983dfcc261be' does not have an implementation.",
    "exceptionType": "System.TypeLoadException",
    "stackTrace": "   at Telerik.Reporting.Common.LicenseValidator.Init()\r\n   at Telerik.Reporting.Common.LicenseValidator.CreateInstance()\r\n   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)\r\n--- End of stack trace from previous location ---\r\n   at System.Lazy`1.CreateValue()\r\n   at Telerik.Reporting.Common.LicenseValidator.get_Instance()\r\n   at Telerik.Reporting.Services.Engine.ReportEngine.GetConfiguration()\r\n   at Telerik.Reporting.Services.AspNetCore.BusinessLogic.ReportsBusinessLogic.GetConfigurationInternal(IReportServiceConfiguration reportServiceConfiguration)\r\n   at Telerik.Reporting.Services.AspNetCore.ReportsControllerBase.GetConfiguration()\r\n   at lambda_method2(Closure, Object, Object[])\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(ActionContext actionContext, IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextExceptionFilterAsync>g__Awaited|26_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)"
}

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Ivet
Telerik team
answered on 06 Feb 2026, 01:00 PM

Hello,

The error 'RuntimeInvalidLicenseStatus' from assembly 'Telerik.Reporting' is a known problem that occurs due to the new version(1.6.40) of the Telerik.Licensing package.

Please visit the Resolving TypeLoadException in Telerik Reporting Related to Telerik.Licensing - Telerik Reporting article for instructions on how to resolve the problem until we release a fix with the next release.

The "undefined isValid" error in the React web report designer is a symptom of the backend configuration error. The designer cannot get a valid configuration from the backend due to the assembly/type error, so it fails to validate the response.

Once the 'RuntimeInvalidLicenseStatus' from assembly 'Telerik.Reporting' error is resolved, the frontend should work as expected.

Let me know if you need additional assistance.

Regards,
Ivet
Progress Telerik

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Trish
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commented on 08 Feb 2026, 08:09 PM

Thank you so much for the information and the link.
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.NET Core .NET Framework Rendering Report Designer - Web
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