The "fix" depends entirely on where you are in your development lifecycle.
The license must be registered in every project that directly references Syncfusion DLLs. That means:
API Fix: In Startup.cs or Program.cs of the API: syncfusion trial license key fix
public void ConfigureServices(IServiceCollection services)
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR_KEY");
// ... rest of services
Fix: You likely have multiple projects in your solution. The project that first loads a Syncfusion control must call RegisterLicense. For example, if your UI layer references a class library that uses Syncfusion, register the key in the UI layer's Main method.
Syncfusion has a known issue where the trial key expiration is cached at the machine level. Fix it like this: The "fix" depends entirely on where you are
The "trial license key fix" is temporary. After 30 days, even a perfectly registered key will fail. You have three options:
Syncfusion offers a free Community License for: API Fix: In Startup
The Community License is full-featured and never expires for your qualifying projects. It’s not a trial. It’s the real product, legally free.
How to get it:
Note: If you are a hobbyist or a solo developer bootstrapping a startup, you likely qualify. Do not struggle with trial resets if you can get this.