react-snap: Error: EISDIR: illegal operation on a directory, open...

@stereobooster Would you tell me How to solve this error ?

$ yarn build
yarn run v1.10.1
$ /Users/sensuikan1973/ReactApp/homepage/node_modules/.bin/react-snap
 ️️️💬  console.log at /: Content is cached for offline use.
 ️️️💬  console.log at /: This web app is being served cache-first by a service worker. To learn more, visit https://goo.gl/SC7cgQ
 ️️️💬  console.log at /: Failed to load resource: net::ERR_UNKNOWN_URL_SCHEME
✅  crawled 1 out of 6 (/)
 ️️️💬  console.log at /programming: Failed to load resource: net::ERR_UNKNOWN_URL_SCHEME
 ️️️💬  console.log at /404.html: Failed to load resource: net::ERR_UNKNOWN_URL_SCHEME
 ️️️💬  console.log at /othello: Failed to load resource: net::ERR_UNKNOWN_URL_SCHEME
 ️️️💬  console.log at /memo: Failed to load resource: net::ERR_UNKNOWN_URL_SCHEME
💬  in browser redirect (/)
⚠️  warning: 404 page title does not contain "404" string
💬  in browser redirect (/)
✅  crawled 2 out of 6 (/programming)
⚠️  warning: 404 page title does not contain "404" string
🔥  error at /404.html { Error: EISDIR: illegal operation on a directory, open '/Users/sensuikan1973/ReactApp/homepage/build/'
    at Object.openSync (fs.js:443:3)
    at Object.writeFileSync (fs.js:1205:35)
    at saveAsHtml (/Users/sensuikan1973/ReactApp/homepage/node_modules/react-snap/index.js:484:8)
    at process.internalTickCallback (internal/process/next_tick.js:77:7)
  errno: -21,
  syscall: 'open',
  code: 'EISDIR',
  path: '/Users/sensuikan1973/ReactApp/homepage/build/' }
💬  in browser redirect (/)
✅  crawled 4 out of 6 (/othello)
💬  in browser redirect (/)
✅  crawled 5 out of 6 (/memo)
 ️️️💬  console.log at /profile: Failed to load resource: net::ERR_UNKNOWN_URL_SCHEME
💬  in browser redirect (/)
✅  crawled 6 out of 6 (/profile)

error Command failed with exit code 1.