Unknown server tag 'telerik:RadPdfViewer'.

[Mikko]

After moving our site to newer version of IIS (10.x), PDF viewer stopped working.

Is there something that it might be missing from web.config etc?

Other components are working file (upload, excel, etc). Also, PDF viewer is working on other sites on the same server.

- Mikko

 

[Rumen]

Hi Mikko,

Happy New Year 2021!

Please make sure that the version of Telerik.Web.UI.dll on the server is at least R1 2020 SP1 (2020.1.219) or later.

This will ensure that the PdfViewer is available and part of the suite.

All mandatory configuration settings of the component are discussed in the Getting Started article.

Best Regards,
Rumen
Progress Telerik

[Mikko]

Hi Rumen,

Thank you and Happy New Year for you too.

Dll was an older version but even with the version 2020.3.2010.40 the problem remains.

Very strange..

Best regards, Mikko

 

 

[Rumen]

Hi Mikko,

It might be due to a caching issue. Can you please close Visual Studio and clean the ASP.NET Temporary Files and the .NET temporary files:

• Clean up the Temporary ASP.NET Files from <sysdrive>:\Windows\Microsoft.NET\Framework[64]\<vernum>\Temporary ASP.NET Files.
• Clean up the Windows WebSite Cache from <sysdrive>:\Users\<UserName>\AppData\Local\Microsoft\WebsiteCache. The location of this cache may vary from one operating system to the next.
• Clean up the Visual Studio Backup from <sysdrive>:\Users\<UserName>\Documents\Visual Studio <vsVersion>\Backup Files. This location depends on your VS settings and installation.
• Clean up the Project Assemblies cache from <sysdrive>:\Users\<UserName>\AppData\Local\Microsoft\Visual Studio\<vsVersion>\ProjectAssemblies. The location of this cache may vary from one operating system to the next.
• If the problem still persists restart the machine.

Best Regards,
Rumen
Progress Telerik

[Mikko]

Hi Rumen,

I'm not sure if that is the issue.

Please notice that the problem only occures on one site on our IIS server. Others are working fine.

We cannot replicate the problem using local Visual Studio projects.

Is it possible that there are other dll files we need to install?

Best regards, Mikko

 

[Rumen]

Hi Mikko,

The only assemblies required for the RadPdfViewer to work are the Telerik.Web.UI.dll and the optional Telerik.Web.Design.dll and Telerik.Web.UI.Skins.dll. Their version should be R1 2020 SP1 (2020.1.219)  or later.

If the same project works fine in your local VS server, but not in IIS, this means that the Telerik.Web.UI.dll is not updated to a version that offers RadPdfViewer (like 2020.3.2010.40) when deploying the project to IIS. Can you please double-check that the version deployed on the server hosting the IIS is indeed  2020.3.1021 (we do not have such a release version 2020.3.2010)? . Open the project's bin folder in Windows Explorer, right-click it and choose Properties to see what's the version in the Details tab. Also please make sure that the Telerik.Web.Design.dll is available in the Bin folder and is the same version as the Telerik.Web.UI.dll.

You can also check whether the project is not obtaining the Telerik assemblies from the GAC and that the references to them in the Solution node of VS are correct.

For your convenience, I also prepared and attached a sample runnable web app that shows how to configure the PdfViewer which you can test on IIS to see how it works.

Regards,
Rumen
Progress Telerik

[Mikko]

Hi Rumen,

Telerik.Web.UI.dll  was an older version and everything is working now.

Thanks!

Best regards, Mikko

[Rumen]

You are welcome, Mikko!

Thank you for confirming the solution! 

Best Regards,
Rumen
Progress Telerik