Quick answer: Unreal Iris not active despite enabling the plugin? Network driver must be set to Iris explicitly - configure NetDriverDefinitions in DefaultEngine.ini.
Iris plugin enabled; multiplayer still uses legacy NetDriver; no Iris benefits.
Set NetDriver in INI
[/Script/Engine.GameNetDriver]
NetConnectionClassName=IrisForces Iris for game traffic.
Verify on game start
Log NetDriver = Iris. Confirms the right driver is active.
Audit per platform
Mobile and console may need additional config. Per-platform .ini overrides.
“Plugin enablement is one step. Driver activation is another.”
If you migrate to Iris, the full configuration is multi-step. Document each; verify activation.