Hi Giorgio,
Thank you for contacting Syncfusion support.
We have analyzed the provided sample and found that you have referred the Script, CSS and the NuGet of different versions in your project so the reported issue occurs. If the CDN link is provided without specifying the version, then it will refer to the latest version, but you have used NuGet packages of 17.1.0.49 in the provided sample. So kindly refer the CDN links with the specific version to resolve the issue.Please find the CDN link with the Version from the below,
Please find the below UG for reference.
We have modified the provided sample and shared the same in the following location,
Please try this and let us know if you have any concerns on this.
Regards,
Akshaya