ISSUE: PIE client cannot stay connected to a remote Dedicated Server. The server closes the connection with CloseReason=MissingLevelPackage referencing a PIE temporary world name.
ENVIRONMENT
- Unreal Engine: 5.5.4 (source build)
- Project: Multiplayer project using World Partition
- Client: PIE (Play-In-Editor), single client
- Server: Packaged Dedicated Server (Development), running on LAN/public network
- Online Subsystem: OSSv2 + EOS (Device ID login)
STEPS TO REPRODUCE
1. Launch DS:
MyGameServer.exe /Game/Maps/Main?listen -log
(Server log shows the map loaded and World Partition initialized.)
2. In the Editor, open the same map and start PIE.
3. In the PIE console, run:
open 192.168.X.X:7777
(Alternatively in code: GetWorld()->GetFirstPlayerController()->ClientTravel(TEXT(“192.168.X.X:7777”), TRAVEL_Absolute)
ACTUAL BEHAVIOR
- Client attempts to connect but is disconnected by the server within a few seconds.
- DS log contains:
LogNet: Close: Reason=MissingLevelPackage, Context: /Memory/UEDPIE_0_Main.Main:PersistentLevel
- Client falls back to the entry map:
Browse: /Game/Maps/Entrance?closed
- Using a packaged client (non-PIE) to the same DS works as expected.
ADDITIONAL OBSERVATIONS
- Client log shows its world is /Memory/UEDPIE_0_Main.Main (PIE temporary world).
- World Partition external actors and data layers are saved and included in the packaged build.
EXPECTED BEHAVIOR
- A PIE client should be able to connect to a remote Dedicated Server similarly to a packaged client, or at least provide a clear error instead of being rejected due to temporary package names.
HYPOTHESIS
- PIEInstanceID / temporary package names used in PIE do not match the DS MapPackageName and cause MissingLevelPackage.
- World Partition runtime level or ActorFolder references may differ in PIE and be considered invalid by the server.
REFERENCES
- UE Forums: Using PIE to connect to Dedicated Server running World Partition crashes
Using PIE to connect to Dedicated Server running World Partition crashes
- Epic Docs: Play in Editor Multiplayer Options
QUESTIONS FOR EPIC
- Is PIE → remote Dedicated Server officially supported in UE 5.5+?
- If supported, are there recommended practices (e.g., prefer Standalone Game over PIE)?
- Any known fixes/CLs for PIE + World Partition + Dedicated Server interoperability?
- Recommended workarounds:
* Map PIE temporary package names to the real map package name when syncing?
* CVar/Editor setting to avoid temporary package names in replication?
* Force a PackageMap refresh before travel?