Minecraft Server Fixes

Fixes · Server Capacity Planning · 2 min read

How to Fix High CPU Usage on Minecraft Server

Fix high CPU usage on Minecraft servers by separating main-thread TPS load, plugins, entities, chunks, Java flags, host limits, and false CPU alarms.

cpu tps performance

Fixes · Profiling and Diagnostics · 2 min read

Minecraft Server Lag Checklist

Use this Minecraft server lag checklist to triage TPS drops, plugins, entities, chunks, hoppers, villagers, CPU, RAM, backups, and player reports.

lag-checklist tps diagnostics

Fixes · Connection Issues · 4 min read

Fix Can't Connect to a Minecraft Server

Fix Minecraft server connection errors by checking startup, server.properties, port forwarding, firewalls, DNS, SRV records, and proxies.

connection port firewall

Fixes · Logs and Crashes · 3 min read

Fix Minecraft Server Exit Code 1

Troubleshoot Minecraft server exit code 1 by reading the first exception, checking Java, plugin versions, startup flags, configs, and host panels.

crash java startup

Fixes · Performance and TPS · 3 min read

Fix Minecraft Server TPS Drops

Fix Minecraft server TPS drops by profiling Spark, checking MSPT, entities, chunks, plugin tasks, view distance, memory, and hosting limits.

tps lag performance

Fixes · Firewalls and Ports · 2 min read

How to Allow Minecraft Server Through Windows Firewall

Allow a Minecraft Java server through Windows Firewall by opening the correct TCP port, checking Java permissions, profiles, private networks, and router forwarding.

windows-firewall firewall port-25565

Fixes · Firewalls and Ports · 1 min read

How to Change Minecraft Server Port

Change a Minecraft server port safely by editing server.properties, updating panel allocations, firewall rules, router forwarding, and DNS SRV records.

server-port port server.properties

Fixes · Firewalls and Ports · 2 min read

How to Check If Port 25565 Is Open

Check whether Minecraft port 25565 is open by confirming server startup, local access, public IP, firewall rules, port forwarding, and external reachability.

port-25565 port-check firewall

Fixes · Access and Authentication · 1 min read

How to Enable Whitelist on Minecraft Server

Enable and manage a Minecraft server whitelist safely with console commands, player names, whitelist reloads, online-mode notes, and proxy considerations.

whitelist access-control security

Fixes · Performance and TPS · 2 min read

How to Fix Can't Keep Up Is the Server Overloaded

Fix Minecraft Can't Keep Up server overloaded warnings by checking TPS, MSPT, Spark profiles, chunks, entities, plugins, world saves, and hosting limits.

cant-keep-up tps mspt

Fixes · Connection Issues · 2 min read

How to Fix Internal Exception Connection Reset

Fix Minecraft Internal Exception Connection Reset by checking network drops, proxies, VPNs, firewalls, resource packs, server load, and protocol plugins.

connection-reset disconnects proxy

Fixes · Access and Authentication · 2 min read

How to Fix Invalid Session on Minecraft Server

Fix Minecraft Invalid Session errors by checking launcher login, Microsoft authentication, online-mode, proxy forwarding, cracked clients, and session refresh.

invalid-session authentication online-mode

Fixes · Server Configuration · 2 min read

How to Fix Kicked for Flying on Minecraft Server

Fix Minecraft kicked for flying errors by checking allow-flight, lag, Elytra, creative mode, anti-cheat plugins, TPS, proxies, and movement checks.

flying movement anti-cheat

Fixes · Connection Issues · 2 min read

How to Fix No Route to Host Minecraft Server Error

Fix Minecraft No Route to Host errors by checking local routing, firewalls, VPNs, public IP, hosting network rules, CGNAT, and server availability.

no-route-to-host connection firewall

Fixes · Domains and DNS · 2 min read

How to Fix Unknown Host on a Minecraft Server

Fix Minecraft Unknown Host errors by checking domain spelling, DNS A records, SRV records, propagation, Cloudflare proxy status, and local DNS cache.

unknown-host dns domain

Fixes · Access and Authentication · 2 min read

How to Fix You Are Not Whitelisted Error

Fix Minecraft You Are Not Whitelisted errors by checking whitelist status, username spelling, UUID changes, online-mode, proxy networks, and permissions.

whitelist access online-mode

Fixes · Connection Issues · 2 min read

Minecraft Server Keeps Disconnecting Players

Troubleshoot a Minecraft server that keeps disconnecting players by checking network drops, proxies, timeouts, plugins, server load, and client errors.

disconnects connection proxy

Fixes · Connection Issues · 2 min read

Minecraft Server Not Showing as Online

Fix a Minecraft server that shows offline by checking startup, status ping, server-port, firewalls, DNS, SRV records, and host panel allocations.

offline connection status-ping

Fixes · Connection Issues · 2 min read

Minecraft Server Timed Out Error

Fix Minecraft server timed out errors by checking startup, public IP, port forwarding, firewalls, CGNAT, DNS, proxies, and player network issues.

timed-out connection firewall

Fixes · Firewalls and Ports · 2 min read

Port Forwarding Not Working for Minecraft Server

Fix Minecraft port forwarding not working by checking server-port, local IP, router NAT, Windows Firewall, UFW, provider firewalls, and CGNAT.

port-forwarding router firewall

Fixes · Access and Authentication · 1 min read

Should You Set online-mode=false?

Learn when online-mode=false is risky, when proxies may require backend offline mode, and how to avoid Minecraft username spoofing and UUID problems.

online-mode offline-mode security

Fixes · Access and Authentication · 1 min read

What Does online-mode Do in Minecraft?

Understand online-mode in Minecraft server.properties, how authentication works, why UUIDs matter, and when proxies use different backend settings.

online-mode authentication security