base64Decode removes pages from a pdf in base64?

I am using dio package to make a GET request to a server to retrieve a PDF file.

The request is working fine, I get the PDF in base64.

I get the response.data, and I use base64Decode to get the Uint8List, I save the file in the storage.

    class FileSaverHelper {
    
      Future<String> save({required String filename, required Uint8List bytes}) async {
    
        final String tempDir = (await getTemporaryDirectory()).path;
        final filePath = "$tempDir/$filename";
        await File(filePath).writeAsBytes(bytes);
    
        return filePath;
    
      }
    
    }
    
    class OpenFileHelper {
    
      final FileSaverHelper fileSaverHelper = Get.find();
    
      Future<void> open({
        required String filename,
        required Future<Uint8List> Function() onDownload
      }) async {
    
        final Uint8List bytes = await onDownload();
        final filePath = await fileSaverHelper.save(
            filename: filename,
            bytes: bytes
        );
    
        if(await File(filePath).exists()){
          OpenFilex.open(filePath);
        }
        
      }

}

When I open the PDF it has only the first page and when I test the base64 that the server sends in the site Base64 to PDF, the PDF decoded has the amount of pages correctly (which is two).

Why after I use base64Decode(response.data), save the PDF to the storage, open it, it has only the first page but in the site the amount of pages is correct?

I found the problem is with the GET request, since the base64 retrieve by the server only through flutter, the file is retrieved incomplete.