The document has an unsupported naming convention or an invalid language code

[anomepani]

I am creating custom training model and I have created project/workspace from ui using Custom Translator Portal
When I am trying to upload a document using this custom sample app using my existing workSpaceId I am getting this error.

Please let me know what I am missing.
The document has an unsupported naming convention or an invalid language code.

Request Code

DocumentDetailsForImportRequest documentdetails = new DocumentDetailsForImportRequest();
            documentdetails.DocumentName = "MyDocPersonelPolicyFINAL"; // Enter document name
            documentdetails.DocumentType = "training"; //values = training/ tuning/ testing
            documentdetails.IsParallel = true; // Enter if this is a parallel document. values = true, false
            documentdetails.FileDetails = new List<FileForImportRequest>();


            FileForImportRequest sourcelanguagefile = new FileForImportRequest();
            sourcelanguagefile.Name = Path.GetFileName(sourcelanguagefilepath);
            sourcelanguagefile.Language = "en"; // Enter source language. Example: de. //Determined from the call to GetCategories 
            sourcelanguagefile.OverwriteIfExists = true; // Enter if you want to overwrite if file exists. values = true, false

            FileForImportRequest targetlanguagefile = new FileForImportRequest();
            targetlanguagefile.Name = Path.GetFileName(targetlanguagefilepath);
            targetlanguagefile.Language = "pt"; // Enter target language. Example: en. //Determined from the call to GetCategories 
            targetlanguagefile.OverwriteIfExists = true; // Enter if you want to overwrite if file exists. values = true, false

            string result = await clientapp.ImportDocument(token_header, Session["ws_id"].ToString(), sourcelanguagefilepath, targetlanguagefilepath, documentdetails, sourcelanguagefile, targetlanguagefile);

Response received

{"jobName":"MyDocPersonelPolicyFINAL","fileProcessingStatus":[{"status":{"displayName":"Failed","id":254},"modifiedDate":"2019-03-29T09:06:05.983","fileName":"MyDoc Personel Policy FINAL.pdf","documentName":"MyDocPersonelPolicyFINAL","summary":"The document has an unsupported naming convention or an invalid language code.\r\n","id":627178,"parentId":null,"language":null},{"status":{"displayName":"Failed","id":254},"modifiedDate":"2019-03-29T09:06:06.203","fileName":"COMPL MyDoc Personel Policy Rev 082817-BR_PT.pdf","documentName":"MyDocPersonelPolicyFINAL","summary":"The document has an unsupported naming convention or an invalid language code.\r\n","id":627179,"parentId":null,"language":null}],"pageIndex":1,"totalPageCount":1}