What common causes are responsible for 'webpack dev server client overlay js errors'?

Common causes include: 1) Incorrectly configured loaders (e.g., a loader not being applied to the expected file type). 2) Missing or incompatible dependencies. 3) Errors within the webpack plugin responsible for the overlay. 4) Problems with Babel configuration if the overlay uses transpiled JavaScript. 5) Circular dependencies that prevent the overlay from loading correctly. 6) Issues with the webpack hot module replacement (HMR) process causing the overlay to not update.