Here is my complete error:
Error: Cannot find module \'ejs\'
at Function._resolveFilename (module.js:317:11)
at Function._load (module.js:262:25)
I ran into this problem after I forgot to install ejs before the first time I ran my app. For some reason ejs was not being seen after installing it later. I found a quick, clean, and effective solution to this problem which was to reinstall express by running npm uninstall express
then npm install express
in the local directory before restarting the server.