This is the most common issue when playing on school or public Wi-Fi. Eaglercraft requires a to communicate with real Minecraft servers. The Fix:
If your school blocks websocket traffic, you may need a browser extension to bypass restrictions. 2. Fix: Extreme Lag or Low FPS
Clear old, broken entries and paste functioning open-source websocket URLs ( wss:// ). eaglercraft 120 1 fix
"Failed to connect to server. IOException: Invalid handshake" or "Connection refused."
Toggle off fire particles and decrease general particle limits If you need more help getting this configured, let me know: This is the most common issue when playing
If you want me to help you find a specific, working Eaglercraft 1.20.1 client, Share public link
: Lower your render settings to 2–4 chunks to minimize the WebGL memory footprint. IOException: Invalid handshake" or "Connection refused
Running modern 1.20 features inside a browser engine causes significant garbage collection overhead. Adjust these exact options within your client profile to stabilize framerates:
Uncheck "Use recommended performance settings" and check . Wipe Domain Site Data
When your browser runs short on local memory, your single-player saves can easily corrupt. To bypass local limitations, use a dedicated standalone file build.
Inside the game's Video Settings, turn off Animations , set Graphics to Fast , and cap your Framerate exactly to your monitor’s refresh rate (e.g., 60Hz) to prevent the browser from overheating your CPU.