You write me:
Port 3000 is already in use, that means that you already run my application, probably Plesk auto restarts. Make sure you stop the application in Plesk and then run it without plesk.
I looked at that thread but unfortunately the link for the file that NeHo asks to upload is no longer available.
Yeah, there was an easy way unfortunately i don't have that one saved either.
Re-populate the database with the updated files.
Close the npm/pm2
Download these 2 files and replace them manually in your vm's directory.
Then navigate through console: cd /var/www/html/app/seed or whatever directory you have installed the server
type : nodejs dbseed.js
Start back npm/pm2 and give it a try.
This issue i believe is mainly for no existing admin in the database (the default ones)