# Troubleshooting

## Document is empty

`[error] Failed reading masterserver authentification response: encountered parse error 'The document is empty.'`

Masterserver needs to request your gameserver for it to be authentified and registered.
This error means that masterserver can't access your server's tcp port.

Multiple problems can cause this error, but you can narrow it down by checking if your server is reachable from the outside.

### Check if server is reachable

You can check if the server is reachable using your internet browser.

example : `http://{server_ip}:{server_tcp_port}/verify` should answer you `I am a northstar server!`

Your server **must** be running while you check if the server is reachable.

### If server is reachable using external IP

**Your GameServer is out of date**

Check that your server is running on the latest Northstar release as it can sometimes include breaking changes.

**MasterServer is down**

Check Northstar's Discord for annoucements.

[https://northstar.tf](https://northstar.tf) giving you a HTTP 523 error means that the masterserver is offline.

**Ports are not the same**

Your gameserver is configured to listen to a given TCP port.

Masterserver needs to be able to contact your gameserver though that same port.

**Another Northstar Server is using the port**

Shutdown every other server to narrow down the problem

This won't generally help but will allow you to avoid checking for the wrong server.

### If server is not reachable using external IP

Check if your server is reachable from your internal network's IP (often starts with `192.168.x.x`)

**Firewall is blocking tcp ports**

In some cases your Firewall or antivirus can prevent your ports to be exposed to your local network.
To fix this issue, make a rule to allow your server to listen on your network.
Disabling the firewall and antivirus can also work, even if it's not reccomended.

### If server is not reachable using external IP but reachable using internal IP

**Router configuration is incorrect**

If your port can be accessed from your local IP but not from your public IP, then it's very likely that your NAT rules aren't properly configured.

**CGNAT**

See [CGNAT](https://r2northstar.gitbook.io/r2northstar-wiki/hosting-a-server-with-northstar/prerequisites#cgnat)

### If server is not reachable using external IP nor using internal IP

Try checking your loopback network interface `http://127.0.0.1:{server_tcp_port}/verify`

**Another program is using the port**

Sometimes another program listens to the same tcp port as Northstar.

You can check if that's the case by running `netstat -a -b` using CMD as admin

As two programs cannot listen to the same port and IP at the same time, changing the TCP listen port can sometimes solve the problem.

**Server is using the wrong port**

You can use `netstat -a -b` using CMD as admin to check which process listens on which port

## Cannot join own dedicated server via serverbrowser but others can

If you're hosting the dedicated server on the same network as the PC you're trying to join it from but are unabled to join it, the reason is likely that your router doesn't support [NAT loopback](https://en.wikipedia.org/wiki/Network_address_translation#NAT_loopback).

The TL;DR is that basically when you connect via serverbrowser to your own dedicated gameserver located on the same network, the message goes to your router where it sees that the gameserver IP requested is the same as its IP address. A router that supports NAT loopback will still check forwarding rules, notice that it goes to your server and "turn the packet around" to your server. A router that doesn't support NAT loopback will simply drop the packet, meaning the request to join will never reach your gameserver.

To work around this you can set `ns_auth_allow_insecure 1` on the gameserver in the `autoexec_ns_server.cfg`. This way you can directly connect to your server via `connect <local gameserver ip>:<port>` (e.g. `connect 192.168.123.456:37015`).

Note that this still won't allow you to join your server via serverbrowser. You will always have to use the `connect` command to join it. Also, setting `ns_auth_allow_insecure 1` means that anyone that knows the server IP can join it without authenticating with masterserver, meaning that they can impersonate any player on your server. \
To resolve this you will have to invest into a router that supports NAT loopback or host your gameserver outside your local network.