License errors

License errors appear when a chat method is called without a valid license. Aspose.LLM does not have an evaluation fallback for inference — every chat operation requires a license.

Symptom

The chat APIs throw:

System.Exception: Not licensed for this method

Or License.IsLicensed returns false when you expected true.

Cause

Several distinct cases:

  • SetLicense was not called before the chat method.
  • SetLicense threw, and your code continued past the failure.
  • The license file path does not resolve to an actual file.
  • The embedded resource name is wrong.
  • The license is expired (especially temporary licenses, typically 30 days).
  • The license is corrupted (partial download, file system damage).

Resolution

1. Confirm SetLicense was called

Every process that calls chat methods must apply the license once. A common mistake is calling SetLicense in one context (e.g., a helper class constructor) and the API in another (a different process).

var license = new Aspose.LLM.License();
license.SetLicense("Aspose.LLM.lic");

// Immediately after, verify:
Console.WriteLine($"IsLicensed: {Aspose.LLM.License.IsLicensed}");
// Should print True. If False, SetLicense failed.

2. Catch exceptions from SetLicense

SetLicense itself can throw when the file is missing, corrupt, or wrong format. Catch and log:

try
{
    var license = new Aspose.LLM.License();
    license.SetLicense("Aspose.LLM.lic");
}
catch (Exception ex)
{
    _logger.LogError(ex, "License could not be applied.");
    throw;
}

The exception message usually states the cause (file not found, parse error, signature check failed).

3. Verify the license file path

When you pass only a file name, SetLicense searches several locations (see Licensing). If the file lives elsewhere, pass the full path:

license.SetLicense(@"C:\licenses\Aspose.LLM.lic");

Confirm the file is copied to the process working directory or bin folder during build:

<ItemGroup>
  <None Update="Aspose.LLM.lic">
    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  </None>
</ItemGroup>

4. Embedded resource — check the name

For embedded licenses, the resource name must match the file name exactly:

<ItemGroup>
  <EmbeddedResource Include="Aspose.LLM.lic" />
</ItemGroup>

license.SetLicense("Aspose.LLM.lic"); // matches the file name

If the file is in a subfolder (e.g., Resources/Aspose.LLM.lic), the resource name becomes <Namespace>.Resources.Aspose.LLM.lic. Match that name exactly, or move the file to the project root.

5. Temporary license expired

Temporary licenses issued by purchase.aspose.com/temporary-license have a fixed expiry date (typically 30 days). After expiry, chat methods throw the same Not licensed for this method error.

Options:

  • Request a new temporary license.
  • Purchase a commercial license.

The application code does not change — swap the .lic file.

6. Corrupt license file

If the file is truncated or modified after issue, signature validation fails. Re-download from the Aspose purchase portal.

7. Stream-based license from a failed source

If you load via a stream:

using var stream = File.OpenRead("Aspose.LLM.lic");
license.SetLicense(stream);

Ensure the stream is at position 0 before SetLicense. If an earlier read consumed bytes, SetLicense sees truncated data.

Prevention

  • Apply the license at application startup, once, with explicit exception handling.
  • Log License.IsLicensed immediately after SetLicense to confirm.
  • Monitor temporary license expiry dates — have a calendar reminder 7 days before expiry.
  • In CI/CD, use an embedded license or pull from a secret store rather than bundling files.
  • For air-gapped deployments, copy the license with the rest of the deployment artifacts.

What’s next

Garbled output Performance issues