Please note that, in order to use specified fonts in a PDF document, these fonts should be present/installed in the machine where PDF is being generated. Please make sure that you have specific fonts installed in your environment and try again. In case issue still persists, please let us know.
Furthermore, it seems you are using an older version of the API and using Aspose.Pdf.Generator approach. Please note that, Aspose.Pdf.Generator has been removed and discontinued in new version of the API and we are not resolving issues or providing support for older approach. You may please upgrade your methods and XML template according to new Aspose.Pdf DOM (Document Object Model) approach (Aspose.PDF for .NET 18.6), by checking following useful articles in API Documentation:
There are no such known issues in our API regarding running on Windows Server 2012. However, as you are using an old version of the API, I am afraid we cannot suggest any workaround unless we are able to replicate the issue with latest version of the API. Please note that issues reported for older versions of the API, are resolved in latest version, which is why we always recommend our customers to use latest version.
Concerning to replicate the issue with latest version, would you please share complete XML template with us. We will try to convert it according to new DOM model, in order to test the scenario in our environment and address it accordingly.