Free Support Forum -

While doing annotation in uploaded PDF file facing an issue


We are already using aspose PDF DLLs. When we are trying to do annotate in uploaded PDF file getting an exception-Please refer exception details in error.png.

For code details please refer attached reference.png.

Here we are using VS-2019 & .Net core 3.0

reference.png (171.7 KB)
error.png (206.4 KB)


We cannot find any attached PDF in your post. Could you please provide it so that we can test the case at our end and address it accordingly.

Attached screens are showing for me. Okay anyway here i am attachingreference.png (171.7 KB)
error.png (206.4 KB)


Its not about the screenshots. We requested for sample PDF file which is causing the error at your side.

sample.pdf (144.0 KB)
Please find attached PDF file.

Please find attached file.

image001.jpg (169 Bytes)

sample.pdf (144 KB)


While loading the document with Aspose.PDF for .NET 21.4, we did not face any exception in our environment. Would you please make sure that you are using the latest version of the API and in case issue still persists, please let us know.

Hi asad ali

I was downloaded latest dll’s, by using that uploaded pdf file, done annotation. When i am trying to read annotations from the pdf file facing an issue. Please refer attached error_annotation screen.sample.pdf (71.2 KB)

error_annotation.png (255.0 KB)


The error is happening because you are using the latest version in a trial mode. If you do not have a valid license which is supported by 21.4 version, you can evaluate it using a free 30-days temporary license. In case you still notice any issue, please let us know.

I downloaded 21.4 DLL’s today with mail Id-
I replaced my bin folder with trail version DLL’s(21.4), still
facing the same issue. Please refer screen shot and PDF file. error_screen.png (221.1 KB)

And also attached DLL screen shot. In the screen shot we can see multiple version DLL folders are there. I tried with net3.5, net4.0 , net3.5_ClientProfile & net4.0_ ClientProfile. TrailDLL_screen.png (140.0 KB).

Present my project is in .NET CORE 3.1


Please use NuGet Package Manager in order to install Aspose.PDF for .NET in your VS Solution. Also, please make sure to use the temporary license as suggested in our previous reply. In case issue still persists, please feel free to let us know.