Why does flight simulator multiplayer keep disconnecting?

Across flight simulators, multiplayer keeps disconnecting when packets are lost, the simulator’s online service or account session fails, players use incompatible builds, or a firewall, VPN or restrictive NAT interrupts traffic. In shared-cockpit sessions, add-on desynchronisation can also remove a player. Diagnose the exact symptom before changing network settings.

Is it a real disconnect or are players simply disappearing?

A session can look disconnected even though your network connection remains active. Microsoft Flight Simulator may hide traffic because players have different server regions, multiplayer modes, group states, data settings or simulator builds. Our explanation of MSFS player visibility and group matching covers those settings without treating every missing aircraft as a network failure.

What usually causes repeated multiplayer disconnections?

The most common cause is packet loss or unstable latency, not insufficient download speed. A fast connection can still drop a real-time session if Wi-Fi interference, a mesh repeater, router congestion or an overloaded connection loses packets. Voice chat or ordinary web browsing may continue because those services recover differently.

Other frequent causes include:

• An expired Microsoft, Xbox, Steam or platform account session.
• A simulator update or multiplayer-client version that does not match the other players.
• A VPN, security suite or firewall filtering the simulator’s traffic.
• Console privacy, parental-control or cross-platform multiplayer restrictions.
• Strict NAT, double NAT or carrier-grade NAT, especially when one player hosts a direct connection.
• A service-side or regional-server interruption affecting several players together.
• Shared-cockpit aircraft, configuration or add-on versions that do not match.

How do I stop flight simulator multiplayer disconnecting?

Test one layer at a time, beginning with connection stability and ending with add-ons. Changing ports, firewall rules and simulator files simultaneously makes the real fault much harder to identify.

1. Confirm what actually drops. Note whether every player disappears, only one friend vanishes, a separate client disconnects, or the whole simulator crashes. Ask whether the other participants lost the session at the same moment; simultaneous failures usually point to the service or host.
2. Stabilise the local connection. Use wired Ethernet temporarily if possible. Pause large downloads, cloud synchronisation and streaming on the same connection, then restart the router and simulator. A continuous check with the operating system’s ping tool can expose recurring loss or large latency swings that a one-off speed test misses.
3. Refresh authentication. Fully close the simulator and its launcher or platform application, then sign out and back in. Set the device clock and time zone automatically because an incorrect clock can invalidate account tokens. For MSFS errors that also report an offline state, follow our checks for sign-in, service and network-filtering failures.
4. Match the session configuration. Install pending simulator and multiplayer-client updates, choose the same server region, recreate the group and verify that online functionality and multiplayer permissions are enabled. On consoles, check the platform account’s multiplayer and cross-play permissions as well.
5. Test VPN and security filtering. Disconnect a VPN temporarily and allow the simulator, launcher and multiplayer client through the firewall. Make one reversible change at a time; do not leave the firewall disabled or open a collection of guessed ports.
6. Check the connection method and NAT. Native server-based multiplayer often works behind ordinary NAT, while direct-host and peer-to-peer sessions are more sensitive to strict NAT, double NAT and carrier-grade NAT. FSX users should first identify whether they are using Steam multiplayer, a boxed-edition direct connection or LAN; our FSX connection-mode guide explains why the required checks differ.
7. Remove add-ons from the test. Reproduce the session with a default aircraft, default scenery and no optional multiplayer utility. Native multiplayer normally substitutes an unknown aircraft rather than disconnecting, so suspect an add-on mainly when the simulator crashes or a shared-cockpit client reports a synchronisation failure.
8. Try another region or host. If several players fail together, recreate the session on another available region. For direct connections, let a participant with unrestricted NAT host. If only one regional service is affected, repeated router or firewall changes will not repair it.

Why does shared cockpit disconnect more often?

Shared cockpit carries synchronised switches, controls and aircraft state in addition to player position, so mismatched aircraft packages or lost packets can cause failures that ordinary multiplayer tolerates. Both pilots should use the same simulator build, aircraft version and compatible configuration.

Direct hosting also fails more readily behind carrier-grade NAT because the router has no publicly reachable address. Use the tool’s relay mode where available or change the host rather than forwarding random ports. For MSFS, the YourControls host, relay and synchronisation checks cover this specific case.

How can I verify that the problem is fixed?

A controlled test separates a genuine repair from a temporary reconnection. Use a default aircraft at a quiet airport, keep every player on the same build and region, and run without optional multiplayer add-ons. Add custom aircraft, scenery and utilities back individually only after the basic session remains stable.

If the disconnection returns, record the exact error wording, time, simulator and platform, server region, connection method, NAT type, active add-ons and whether other players dropped simultaneously. A failure that recurs after a consistent interval often points to authentication expiry, router time-outs, Wi-Fi power management or a multiplayer client rather than raw connection speed.