What's wrong with radiks-server after yarn add?

#1

~$ PORT=2319 radiks-server
internal/modules/cjs/loader.js:638
throw err;
^
what’s wrong with radisk-server after yarn add?

npm install -g radiks-server

or, if you use yarn

yarn global add radiks-server

Error: Cannot find module ‘…/index’
at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
at Function.Module._load (internal/modules/cjs/loader.js:562:25)
at Module.require (internal/modules/cjs/loader.js:690:17)
at require (internal/modules/cjs/helpers.js:25:18)
at Object. (/usr/lib/node_modules/radiks-server/bin/radiks-server.js:5:19)
at Module._compile (internal/modules/cjs/loader.js:776:30)
at Object.Module._extensions…js (internal/modules/cjs/loader.js:787:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)

@yunsite