Licensing checks are performed by a standard Unreal Engine module provided by Epic Games, known as PluginWarden. This module communicates with the Epic Games Launcher (EGL) to verify your entitlements on the remote Fab/UE Marketplace back-ends. In this section, we have compiled solutions for the most common issues related to this Unreal Engine module.
To ensure that PluginWarden can communicate effectively with the Epic Games Launcher (EGL), please make sure that:
If the problem persists, try rebooting your PC to force EGL to refresh its local data and reconnect to the back-ends, then try again.
If the issue continues, please proceed to the next section.
Unreal Engine communicates with the Epic Games Launcher (EGL) using a standard plugin called UDP Messaging. Ensure this plugin is enabled for your project by following these steps:
After enabling the plugin, restart your project. If the issue remains, continue to the next section.
The system firewall may block communication between the Unreal Engine editor and the Epic Games Launcher (EGL). To quickly determine if this is the cause, temporarily disable your firewall:
Restart your project; if the problem is resolved, re-enable your firewall and configure it to allow communication between the Unreal Engine editor and EGL:
If the issue persists even with the firewall turned off, please restore the firewall and proceed to the next section.
The UDP Messaging module used by the Unreal Engine editor and the Epic Games Launcher (EGL) may encounter issues when Virtual Network Adapters (often used by VPN systems) are present. To determine if this is the case:
<PROJECT>\Saved\Logs\<PROJECT>.log
);LogUdpMessaging: Initializing bridge on interface 0.0.0.0:0 to multicast group 230.0.0.1:6666.
LogUdpMessaging: Initializing bridge on interface 0.0.0.0:0 to multicast group 230.0.0.1:6666. LogUdpMessaging: Display: Unicast socket bound to '0.0.0.0:64695'. LogUdpMessaging: Display: Added local interface '192.168.75.42' to multicast group '230.0.0.1:6666'
LogUdpMessaging: Initializing bridge on interface 192.168.1.124:0 to multicast group 230.0.0.1:6666. FUdpSocketBuilder: Failed to bind UdpMessageUnicastSocket to 192.168.1.124:0. Error code 21. LogUdpMessaging: Error: StartTransport failed to create unicast socket on 192.168.1.124:0
If your log contains a similar error, it indicates that another program (typically a Virtual Network Adapter or a VPN) is already using the necessary communication port, preventing the Unreal Engine editor from communicating with EGL. To resolve this issue, try the following:
For more information and additional options, please refer to FUdpSocketBuilder errors causing frame rate drops but no networking in project.
If the issue still persists, you will need to collect several log files to share with Epic Games for further investigation:
<PROJECT>\Saved\Logs\
;If the issue cannot be resolved — since the problem lies between Epic Games' components (PluginWarden failing to connect to EGL, and/or EGL failing to validate your purchase with the Fab/UE Marketplace back-ends) — please contact Fab/UE Marketplace Support by Epic Games (Fab Support, UE Marketplace Support) and report that PluginWarden fails to validate your purchase. Be sure to provide the collected ZIP archives.