It sounds more like a networking issue than an application issue if you can see it from localhost. Check the following:
- Check if your computer is running a firewall blocking port 9988, or a port range that excludes it. Firewalls can come from the OS, and some antivirus packages -- since 9988 is a non-standard port for http it might be mis-identifying it as malware.
- Check if there's something on your network blocking it the port (e.g. a corporate firewall, etc).
- Check to see if your hostname has a DNS record that resolves properly. You can find this out through tools like nslookup. It could be that there is no record, the record is out of date, etc. You can also try using the computer's IP address instead of the hostname to see if it works like that, e.g.