I found a lot of topics with this error.. But i don't find a solution.
I have exactly the same error "Cannot GET /" when i try ionic serve, i follow exactly the process to install node, ionic ect..
but without success.
But it's not customization.. a lot of personne who buy this app have this error. A customization is when we want a thing different qnd need create adaptation specially for one personn. It's not that case
I found the solution
I uninstall all (node ect..), i installed the version 8.10.0 of NodeJs and i follow this https://gist.github.com/shubham-99fusion/b9390410773f70106d329e7de885c932
it was my node version the problem