Sounds like you are hitting a known issue which has been fixed in 4.3.1 Agent version. Can you try instaling this version and verify if the issue persisis
You can download it from https://download.appdynamics.com/download/
Getting this error in a .NET app after installing the appdynamics agent, it goes away if I uninstall it:
System.IO.FileNotFoundException.Could not load file or assembly 'Newtonsoft.Json, Version=18.104.22.168, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The system cannot find the file specified.
Solved! Go to Solution.