Troubleshooting a running application can be difficult, usually it starts around checking log output and then following through the likely code paths to get an idea of where a failure may occur. In a development environment, you might attach a debugger a step through source, but troubleshooting isn't always that convenient. There are several helpful tools that can assist, but one that gives the most comprehensive view of a running application is strace. With strace you are able to see all of the system calls an application makes to get a detailed understanding of what is going on "under the hood" in order to troubleshoot an issue.
Take a simple "hello world" F# application, the kind you get from dotnet new console -lang F# -n strace-sample". Build it with dotnet build and then launch it with strace to get a trace of all the system calls in a file called trace.log(adjusting for your build output path if on a different framework vers