Yes you can. The thing you need to note is that you can't run two different node apps on same port.
Why this is not working for you I'm not sure, you can specify which file you want to start:
- forever start example.js --spinSleepTime 10000
Maybe specifying redundancy can help (how much times script can be run, there is example in docs):
- forever -m5 start server.js --spinSleepTime 10000
You can look at forever docs a their GitHub for more explanation.
If you really can't make it work, try
pm2. There is great DigitalOcean tutorial about using it.