Hi Jair,
Thanks for contacting Syncfusion Support.
The reported issue might be occurred due to lingering of old assembly in your application. So, please ensure latest assemblies are deployed and no duplicate old assemblies are referred.
To resolve this kind of issues, please try out the below suggestion:
· Clear bin and obj folders exists in the application directory.
· Restart the Visual Studio, then clean the solution and rebuild the application.
If still you have any issue, please share the below details.
· Whether you are using VS2015 or VS2017 to create the ASP.NET Core application.
· If you have VS2015, share your project. json file and share the screenshot of references that has been referred in Solution Explorer tab.
· If you have VS2017, share your .csproj file. This will be helpful for us to analyze and provide a solution at the earliest.
Regards,
Francis Paul A.