Immediate Fix
Slack Error 104 is primarily a connection reset issue. The fastest way to resolve this is to clear the application cache and force a fresh handshake with Slack’s servers.
Follow these steps to clear the cache on the Slack Desktop app:
| Step | Action |
|---|---|
| 1 | Click on the Hamburger Menu (three horizontal lines) in the top-left corner. |
| 2 | Navigate to Help > Troubleshooting. |
| 3 | Select Clear Cache and Restart. |
If you are using Slack in a web browser, try opening the application in Incognito/Private mode. This bypasses existing cookies and extensions that might be interrupting the connection.
Technical Explanation
Technically, Error 104 corresponds to a ECONNRESET message. This happens when the connection is unexpectedly closed by the peer (the Slack server or an intermediate proxy).
In most enterprise environments, this error is triggered by a TCP Reset (RST) packet. This packet is often sent by a firewall or a Deep Packet Inspection (DPI) tool that deems the Slack traffic suspicious or timed out.
It can also occur due to local network instability where the socket becomes stale. When Slack attempts to reuse a closed socket, the OS returns Error 104.
Alternative Methods
1. Flush DNS Cache
Sometimes your local machine maps Slack’s domain to an outdated IP address. Flushing your DNS forces the system to request new routing information.
Open your terminal or command prompt and run the following command:
ipconfig /flushdns2. Disable VPN or Proxy
Slack Error 104 is frequently caused by VPNs that rotate IP addresses mid-session. Try disconnecting your VPN or adding Slack to your proxy’s whitelist (split-tunneling).
3. Update Network Drivers
Outdated network interface card (NIC) drivers can struggle with modern WebSocket connections used by Slack. Ensure your drivers are updated via your device manager.
If none of these work, try switching from a Wi-Fi connection to a wired Ethernet connection to rule out packet loss during the TLS handshake.