Hi Prakash,
It looks like the license keys are not properly registered in your application.
If you are using Syncfusion assembliesuget packages from the installer or from nuget.org , you should generate and register the corresponding version and platform license key in your application to avoid the trial license warning.
https://help.syncfusion.com/common/essential-studio/licensing/overview
To know about generating license key,
https://help.syncfusion.com/wpf/licensing/how-to-generate
Syncfusion license keys are version and platform-specific and the generated license key is just a string that needs to be registered before any Syncfusion control is initiated.
To know about registering license key,
https://help.syncfusion.com/wpf/licensing/how-to-register-in-an-application
Please, ensure that all the referenced Syncfusion assemblies\NuGet packages are all on the same version(20.3.0.47) as license key’s version(20.3.0.47) in your project.
Find the below knowledge base article to know about which version license key should use in application,
https://www.syncfusion.com/kb/8951/which-version-syncfusion-license-key-should-i-use-in-my-application
Note: If you’ve upgraded both the license key and assembliesuget packages, could you please try cleaning your project, deleting the bin\obj folders and rebuild your application, then check whether it resolves the issue?
Please follow the below kb article to know more information on removing the license warning message.
https://www.syncfusion.com/kb/12756/how-to-resolve-syncfusion-license-popup-message-or-trial-message-warning
If the reported issue is still not resolved, please share us the following details to check the issue from our side,
1. List of Syncfusion NuGet packages\assemblies used and their version,
2. TargetFrameWork of your application,
3. Screenshot of the license key registered in your application.
4. Visual Studio version which you are using.
Regards,
Jeyaseelan M