I get the following message

[Arman Mukatov]

ERROR in ./src/containers/SupportPage/SupportInner.less
Module build failed (from ./node_modules/mini-css-extract-plugin/dist/loader.js):
ModuleError: Module Error (from ./node_modules/postcss-loader/dist/cjs.js):
Loading PostCSS "postcss-import" plugin failed: The "path" argument must be of type string. Received undefined

(@/project/src/containers/SupportPage/SupportInner.less)
at Object.emitError (/project/node_modules/webpack/lib/NormalModule.js:524:6)
at getPostcssOptions (/project/node_modules/postcss-loader/dist/utils.js:222:19)
at Object.loader (/project/node_modules/postcss-loader/dist/index.js:57:42)
@ ./src/containers/SupportPage/SupportInner.js 9:0-50 88:17-40 90:17-41 92:17-41 98:66-88 105:17-42 112:21-46 117:21-45 119:21-43
@ ./src/containers/SupportPage/Loadable.js 108:13-50 81:21-85:3
@ ./src/routes.js 6:0-82 40:15-26 43:15-31
@ ./src/client.js 17:0-28 86:30-36

webpack-5.28.0
postcss-8.2.8
postcss-import-14.0.0
postcss-loader-5.2.0
postcss-preset-env-6.7.0

postcss.config.js

module.exports = ({ file }) => ({
    plugins: {
      'postcss-import': {
        root: file.dirname
      },
      'postcss-url': [
        {
          filter: './**.*',
          url: asset => `./${asset.url}`
        },
      ],
      'postcss-preset-env': {
        stage: 3,
        browsers: 'last 2 version',
      },
      'postcss-browser-reporter': {},
      'postcss-reporter': {},
      'cssnano': {},
    }
});

webpack config:

{
        test: /\.less$/,
        use: [
          {
            loader: MiniCssExtractPlugin.loader
          },
          {
            loader: 'css-loader',
            options: {
              modules: {
                localIdentName: 'k_[hash:base64:5]'
              },
              importLoaders: 2,
              sourceMap: true
            }
          },
          {
            loader: 'postcss-loader',
            options: {
              sourceMap: true
            }
          },
          {
            loader: 'less-loader'
          }
        ]
      },

[Alexander Akait]

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Bug in postcss-import, please read message