An 'ArgumentError' occurs when a function receives an argument it cannot handle. Check the function's expected inputs and ensure you're passing the correct data types and structures.

The 'ArgumentError' in Elixir is typically raised when a function receives an argument that is inappropriate for its expected input. This can happen due to a variety of reasons, such as incorrect data types, unexpected values, or improperly formatted data structures. To resolve this issue, start by examining the function definition to understand what types of arguments it expects. For instance, if a function is designed to work with integers and you pass a string, you'll encounter an 'ArgumentError'. To troubleshoot, look closely at the stack trace provided with the error message; it will help you identify the function call that caused the error. Once identified, you can validate the inputs before passing them to the function. Implementing type checks or guards can help ensure that the arguments are valid. Moreover, consider writing unit tests to cover various input scenarios to catch potential issues early in development. By understanding the expected argument types and ensuring proper input validation, you can effectively address 'ArgumentError' occurrences in your Elixir applications.