Code :
var doc = new Document(filename);
doc.Save(fileout, SaveFormat.Markdown);
Error stack :
System.NullReferenceException: Object reference not set to an instance of an object.
at #=zFz9$AL7bjxwHUuimODfFc8swDugx.#=zHNdoAxA=(TextState #=zDTORIt0=)
at #=z0zN0M7e_lSCqINW$COyisUCpne7x.#=zL68jzBMbD07I(#=z2dxE15_qs_ivq3ntgDIeEy5wkg3vEKizMg== #=z7BPwp$w=)
at #=zPLF21rcCjqT4wK9sLTv9f8SYMqBQ.#=zR5N0FI0=(#=z2dxE15_qs_ivq3ntgDIeEy5wkg3vEKizMg== #=z8WyUkEPD6eKI)
at #=z2dxE15_qs_ivq3ntgDIeEy5wkg3vEKizMg==.#=zein5aVQ=(#=zBkPftE8MwO24vJjILIMBSyhoNhXiHSkDug== #=zIPO4KHo=)
at #=zPLF21rcCjqT4wK9sLTv9f8SYMqBQ.#=zR5N0FI0=(#=zDuAeEYfjAqWUQUAL73gmGyl3nEfi #=z6HkLDoQXRpSN)
at #=zEYtg64iGdHhc8gg7Ah7TCNPaml_n.#=zR5N0FI0=(#=zWgAljL3aD6sd_9F3zxkrTGYZWNZ_SBlY1A== #=z$pluq300W1aZ)
at #=zWgAljL3aD6sd_9F3zxkrTGYZWNZ_SBlY1A==.#=zein5aVQ=(#=z8bm0xLkXOiaZEthMymP6rwJdGZz8Mn9VWA== #=zIPO4KHo=)
at #=zEYtg64iGdHhc8gg7Ah7TCNPaml_n.#=zR5N0FI0=(#=zZTI9LENSdGjT36pl79HaBQk6EnNf #=zERIdzgP$liKC)
at #=zZTI9LENSdGjT36pl79HaBQk6EnNf.#=zein5aVQ=(#=z8bm0xLkXOiaZEthMymP6rwJdGZz8Mn9VWA== #=zIPO4KHo=)
at #=zEYtg64iGdHhc8gg7Ah7TCNPaml_n.#=zR5N0FI0=(#=zaLXqLPnjyWdAITJjpYRmjpMIgoaG #=zr_Izd3RgLcEx)
at #=zSkLndZFqx3SJlELTnFXS3m0kmE2nPNAsaA==.#=zgqfhwsE=(Document #=zGcWNaW4=, MarkdownSaveOptions #=z5hrkyKQ=)
at #=zSkLndZFqx3SJlELTnFXS3m0kmE2nPNAsaA==.#=zRjYyL8GLOU5ZTK_7aQ==(Document #=zGcWNaW4=, String #=zwa$d12k=, MarkdownSaveOptions #=z5hrkyKQ=)
at Aspose.Pdf.Document.#=zrO8FjNQBRWPB(String #=zIRfqktcuWgdf, SaveOptions #=z5hrkyKQ=)
at Aspose.Pdf.Document.#=zORns2n_QCEsH(String #=zIRfqktcuWgdf, SaveOptions #=z5hrkyKQ=)
at Aspose.Pdf.Document.Save(String outputFileName, SaveOptions options)
at Program.<Main>$(String[] args) in
Aspose.PDF 25.5.0 C#8 on Windows.