How to resolve the runtime error in ASP.NET Web Forms

How to resolve the runtime error in ASP.NET Web Forms

The conflict occurs because of the mismatched framework version of Web.config and referred DLL. Refer to the assembly DLL version which matches with the framework version used in the application. And also, all the assemblies referred inside the Web.config file should match .NET framework version.  

For example: In 14.3.0.49 build, if the .NET framework version of your application is 4, then refer the DLL which is present in the folder C:\Program Files (x86)\Syncfusion\EssentialStudio\14.3.0.49\precompiledassemblies\14.3.0.49\4.0, also give version details as 14.3400.0.49 in the assembly information of Web.config file.  

The assembly version should be same for the following cases.  

1. Web.config  
2. In Register directives  
3. Referred DLL  

The previously listed things should have the same framework version.   

Please find the following references.

You can also have migration tool, where you can migrate the Syncfusion project with another version. Please find the following reference link.  

UG link: https://help.syncfusion.com/extension/aspnet-extension/project-migration