Thanks for your patience. We have received a response from the product team and they required the following details.
- Type of the user account used for scheduler (Administrator or Standard User account)
- Type of the user account used for WCF Service (Administrator or Standard User account)
Furthermore, as you are using version 17.4.0 of GroupDocs.Viewer for .NET, therefore, we have created a custom build (download) of version 17.4.0 for you. In this custom build, the product team has changed the list of required permissions to open Mutex. Please try the custom build of GroupDocs.Viewer at your end and check if the issue persists. The product team also suggested to try running both applications (scheduler and web app) under the same account and check if the issue persists.
Important: The provided custom build is only for testing and it will work for 7 days and will stop working on 01/30/18. In case it helped to fix the issue we’ll prepare fully functional build without 7 days limitation.