Problem with license on viewer

Hi, today I have some issues with some of our customer that complain about the appearance of the message “evaluation only”.
I don’t change anything, nor the version of the dll not even the license file.
Currently I have license file that has the tag 20180109 and file version of groupdocs.viewer is 17.12, that has been released on 12/21/2017 according to your site (https://downloads.groupdocs.com/viewer/net/new-releases/groupdocs.viewer-for-.net-17.12-(dlls-only)/ .
I also check that the folder where are located license and dll are reachable and not read-only.

Can you help me?

Thank you

@gian_boscolo_hotmail_it,

The evaluation watermark appears when the license is not initialized or there is some exception while applying the license, therefore, the following points might be helpful for you regarding the licensing issue:

  • Make sure the input documents do not already have the evaluation message.
  • Check if your code does not catch an exception thrown by GroupDocs.Viewer licensing code.
  • Clear GroupDocs.Viewer’s cache folder and try again.

As you have mentioned that the issue is happening only for a few customers, we would suggest you to use some mechanism to log the exceptions/errors that occur in your application. This will surely help you in tracing the issue.