System.Reflection.AmbiguousMatchException: ‘Ambiguous match found.’ Error on SetLicense

We have Aspose Slides working with out license file in a .Net Core 2.2 Web API application. We are now upgrading a .Net Core 1.1 app to Core 2.2 and integrating our code from the Web API into the Web App and decommissioning the Web API.

I am using the same License file for both. I have included the latest NuGet Aspose.Slides package. Both have the same SetLicense call in their respective startup classes.

The Web API runs fine. The web app fails with the “Ambiguous match found” error. Only one is running at a time.

What can cause the error and how to resolve?


I have observed the issue shared by you and request you to please share the working sample project reproducing the issue on your end. I also suggest you to please try using latest Aspose.Slides for .NET 20.3 on your end if you are using older version.

I cannot post the project for company privacy issue but am including the relevent non-identifiable parts:

License file:
image.png (40.1 KB)

public void ConfigureDevelopmentServices(IServiceCollection services)

Aspose.Slides.License license = new Aspose.Slides.License();


No other Aspose products are included in the solution.
target framework = netcoreapp2.2


I have tried understanding the issue on your end and have not been able to completely understand that. Can you please share the license file and sample project (not all) reproducing the issue on your end so that we may try to investigate the issue on our end. Please also share the stack trace obtained on your end too.