Changing port cause stuck at "Starting your app"

help
1 
git clone https://github.com/mertyildiran/Dermatron.git
cd Dermatron/
meteor npm install
meteor

It’s OK. App running at: http://localhost:3000/ No problem.

meteor --port 6060

It stuck at Starting your app

meteor reset
meteor --port 6060

It’s OK. App running at: http://localhost:6060/ No problem.

What can cause this? How can I resolve?