livereload with mkcert file pairs for https

[dwlamb]

I am trying to configure grunt-contrib-watch livereload to work with a local development server which has https characteristics using mkcert. Not succeeding finding an example specific to mkcert, I tried adapting the example from the documentation for SSL key/cert file pairs. This:

watch: {
  css: {
    files: '**/*.sass',
    tasks: ['sass'],
    options: {
      livereload: {
        host: 'localhost',
        port: 9000,
        key: grunt.file.read('path/to/ssl.key'),
        cert: grunt.file.read('path/to/ssl.crt')
      }
    },
  },
},

adapted to:

watch: {
  css: {
    files: '**/*.sass',
    tasks: ['sass'],
    options: {
      livereload: {
        host: 'localhost',
        port: 9000,
        key: grunt.file.read('path/to/test.com-key.pem'),
        cert: grunt.file.read('path/to/test.com.pem')
      }
    },
  },
},

It did not work. grunt returned the following.

Error: Unable to read "path/to/test.com-key.pem" file (Error code: ENOENT).
Warning: Task "default" not found. Use --force to continue.

What is the method for using livereload on https sites using mkcert?