npm uninstall node-sass
npm install node-sass@latest
If it still doesn't work, compare the node.js version of package.json. If it is different from the installed version, try reinstalling node.js.
node -v View node.js version
npm -v
npm uninstall node-sass
npm install node-sass@latest
If it still doesn't work, compare the node.js version of package.json. If it is different from the installed version, try reinstalling node.js.
node -v View node.js version
npm -v