//Docentric document generation pdf
            using (Stream templateStream = new MemoryStream(bytes))
            {
                using (MemoryStream documentStream = new MemoryStream())
                {
                    DocumentGenerator dgPdf = new DocumentGenerator(xmlDoc);

                    //Byte for pdf
                    dgPdf.GenerateDocument(templateStream, documentStream, SaveOptions.Pdf);
                    byte[] bytesForPdf = documentStream.ToArray();

                    templateBase64String = Convert.ToBase64String(bytesForPdf);
                }
            }

System.Exception: 'Cannot initialize FontManager because no font sources have been set and hence no fonts are available. Use the 'FontManager.SetFontsSources' method to specify font sources.'

This occurs at the dgPdf.GenerateDocument() method.