Quick Summary
The "103 Unknown Host" error in Discord typically indicates that your computer is unable to resolve the Discord domain name to an IP address, meaning it can't find the Discord server you're trying to connect to. This is often due to DNS issues, network connectivity problems, or Discord server-side issues.
Common Causes
- DNS Resolution Failure: Your computer is unable to translate the Discord domain name (e.g., discord.com, cdn.discordapp.com) into the correct IP address due to a problem with your DNS server or DNS settings.
- Incorrect DNS Server: Your computer is using a DNS server that is either unreliable, outdated, or experiencing issues, leading to incorrect or missing DNS records for Discord.
- Network Connectivity Issues: There might be problems with your internet connection preventing you from reaching the DNS server needed to resolve Discord's address. This could also indicate local network configuration issues.
- Discord Server-Side Issues: Although less common, the "103 Unknown Host" error can sometimes be caused by problems on Discord's servers, such as outages or DNS propagation issues.
- Firewall or Security Software Interference: Your firewall or other security software is blocking Discord's access to the network, particularly DNS resolution requests.
Step-by-Step Fixes
Method 1: Flush DNS Cache
Windows:
Step 1: Open Command Prompt as administrator (search for "cmd", right-click, and select "Run as administrator").
Step 2: Type ipconfig /flushdns and press Enter.
Step 3: Type ipconfig /registerdns and press Enter.
Step 4: Type ipconfig /release and press Enter.
Step 5: Type ipconfig /renew and press Enter.
macOS:
Step 1: Open Terminal (Applications > Utilities > Terminal).
Step 2: Run the command sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder (you will be prompted for your password).
Step 3: Restart your browser and Discord.
Method 2: Change DNS Servers
Step 1: Open your network settings (Windows: Control Panel > Network and Internet > Network and Sharing Center > Change adapter settings. macOS: System Preferences > Network > Select your connection > Advanced > DNS).
Step 2: Change your DNS servers to a public DNS server like Google DNS (8.8.8.8 and 8.8.4.4) or Cloudflare DNS (1.1.1.1 and 1.0.0.1).
Step 3: Save the changes and restart your computer.
Method 3: Restart Your Router and Modem
Step 1: Power off your modem and router.
Step 2: Wait for about 30 seconds.
Step 3: Power on your modem and wait for it to fully initialize.
Step 4: Power on your router and wait for it to fully initialize.
Step 5: Try running Discord again.
Method 4: Check Firewall/Antivirus Settings
Step 1: Ensure that Discord is allowed through your firewall and antivirus software. Look for exceptions or allowed applications lists in their settings and make sure Discord is included.
Step 2: Temporarily disable your firewall/antivirus to see if the issue persists. If the problem is resolved, adjust your firewall/antivirus settings accordingly.
Method 5: Check Your Hosts File
Step 1: On Windows, open Notepad as administrator.
Step 2: Open the hosts file located at C:\Windows\System32\drivers\etc\hosts.
Step 3: Look for any lines that mention Discord or discord.com. If you find any, remove them (unless you intentionally added them).
Step 4: Save the hosts file and restart your computer.
Step 5: On macOS, open the Terminal, type in sudo nano /etc/hosts and enter your password, edit as required and Ctrl+X to save.
Method 6: Reinstall Discord
Step 1: Completely uninstall Discord from your computer.
Step 2: Download the latest version of Discord from the official Discord website (discord.com).
Step 3: Install Discord and try running it again.