The error 'Objects are not valid as a React child' commonly occurs in React development when attempting to render a plain object directly within JSX.To fix this error, you should use JSON.stringify() to serialize the object before rendering it inside JSX.Using JSON.stringify() ensures that the object is converted into a displayable string format that can be rendered in React components.By mastering the basics of state handling and JSX rendering, developers can avoid common errors like rendering raw objects in React applications.