This issue may arise if you have installed Syncfusion Essential Studio with all the product components including Silverlight in the IIS-configured machine. This is a known issue, and it will be fixed starting from version 11.x.x.xx of Syncfusion Essential Studio.
As a workaround, you can resolve it by running Aspnet_regiis.exe with the below arguments to re-register the correct version of ASP.NET in the IIS web server.
2. Run Aspnet_regiis.exe with the following arguments: aspnet_regiis.exe /iru
3. Refresh the IIS web server or run the iisreset command in admin mode and restart the Syncfusion dashboard.
This page will automatically be redirected to the sign-in page in 10 seconds.