When Serilog is not behaving as you expect, this may be caused by an internal exception or configuration issue. Here are a couple of ways to sort things out.

First, Serilog will write simple diagnostic messages to user-specified output if provided. Call SelfLog.Enable() at program startup:

Serilog.Debugging.SelfLog.Enable(msg => Debug.WriteLine(msg));

The system console, a file or an in-memory StringWriter can all be used to collect Serilog's output by providing a TextWriter instead of a delegate:

Serilog.Debugging.SelfLog.Enable(Console.Error);

Serilog never writes its own events to user-defined sinks.

Warning: SelfLog does not perform any synchronization over the provided TextWriter. For most implementations you should use the TextWriter.Synchronized() method to ensure the object being passed in can be written from multiple threads:

var file = File.CreateText(...);
Serilog.Debugging.SelfLog.Enable(TextWriter.Synchronized(file));

Most Serilog packages include debug symbols (_.PDB) on https://symbolsource.org - adding it as a symbol server in Visual Studio can help when determining the cause of an exception from a sink.

A Roslyn-based analysis for code using the Serilog logging library. Checks for common mistakes and usage problems. You can find more information here.