Crashing because of an Online Subsystem error

Well, I had a Unreal Engine 5 Early Access Blueprint Project with a non-dedicated multiplayer system set up using advanced sessions (for 4.26 with minor tweeks). It worked fine in during PIE but I couldn’t package it.

So I started with changing all code back from advanced to simple sessions (Find Session, Create Session nodes). Later I deleted everything related to online connection from the DefaultEngine.ini, kept only:

DefaultPlatformService=Null

I also removed the Steam Subsystem plugin from the options. Now - sometimes - whether I’m testing single player or multiplayer sessions, I get the error below. The exact context is: I open PIE at the main menu>I load/create a new game (solo/LAN/online, it doesn’t matter as far as I can tell)>I open the game level using the option listen> the level barely loads and then crashes.

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x00000007000001f0

0x00007ffefa85fa31 UnrealEditor-Engine.dll!UEngine::GetWorldFromContextObject() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\UnrealEngine.cpp:11383]
0x00007ffeebf284d3 UnrealEditor-OnlineSubsystemUtils.dll!FOnlineSubsystemBPCallHelper::FOnlineSubsystemBPCallHelper() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemUtils\Source\OnlineSubsystemUtils\Private\OnlineSubsystemUtils.cpp:799]
0x00007ffeebf83716 UnrealEditor-OnlineSubsystemUtils.dll!UFindSessionsCallbackProxy::OnCompleted() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemUtils\Source\OnlineSubsystemUtils\Private\FindSessionsCallbackProxy.cpp:65]
0x00007ffeebf64ca9 UnrealEditor-OnlineSubsystemUtils.dll!TBaseUObjectMethodDelegateInstance<0,UFindSessionsCallbackProxy,void __cdecl(bool),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:611]
0x00007ffeebe97d61 UnrealEditor-OnlineSubsystemNull.dll!TMulticastDelegate<void __cdecl(bool),FDefaultDelegateUserPolicy>::Broadcast() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:955]
0x00007ffeebe9f94e UnrealEditor-OnlineSubsystemNull.dll!TBaseRawMethodDelegateInstance<0,FOnlineSessionNull,void __cdecl(void),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:469]
0x00007ffeec84ac9d UnrealEditor-OnlineSubsystem.dll!TMulticastDelegate<void __cdecl(void),FDefaultDelegateUserPolicy>::Broadcast() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:955]
0x00007ffeec8a3364 UnrealEditor-OnlineSubsystem.dll!FLANSession::Tick() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystem\Source\Private\LANBeacon.cpp:305]
0x00007ffeebebc87b UnrealEditor-OnlineSubsystemNull.dll!FOnlineSessionNull::Tick() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemNull\Source\Private\OnlineSessionInterfaceNull.cpp:961]
0x00007ffeebebcc10 UnrealEditor-OnlineSubsystemNull.dll!FOnlineSubsystemNull::Tick() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemNull\Source\Private\OnlineSubsystemNull.cpp:178]
0x00007fff1147811c UnrealEditor-Core.dll!FTicker::Tick() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\Containers\Ticker.cpp:95]
0x00007ff6b358c14e UnrealEditor.exe!FEngineLoop::Tick() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5246]
0x00007ff6b35a0b2c UnrealEditor.exe!GuardedMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:171]
0x00007ff6b35a0c0a UnrealEditor.exe!GuardedMainWrapper() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:137]
0x00007ff6b35b573d UnrealEditor.exe!WinMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:268]
0x00007ff6b35b86ba UnrealEditor.exe!__scrt_common_main_seh() [d:\agent_work\5\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
0x00007fff81b87034 KERNEL32.DLL!UnknownFunction
0x00007fff82c42651 ntdll.dll!UnknownFunction

I’m on this problem for 3 days now, don’t know what to search on google, unreal forums and reddit anymore. I tried configuring the Steam Subsystem plugin back again using this config:

[/Script/Engine.GameEngine] 
+NetDriverDefinitions=(DefName="GameNetDriver",DriverClassName="OnlineSubsystemSteam.SteamNetDriver",DriverClassNameFallback="OnlineSubsystemUtils.IpNetDriver")

[OnlineSubsystem] 
DefaultPlatformService=Steam

[OnlineSubsystemSteam] 
bEnabled=true 
SteamDevAppId=480

[/Script/OnlineSubsystemSteam.SteamNetDriver]
NetConnectionClassName="OnlineSubsystemSteam.SteamNetConnection"

and still got a crash error.

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0xffffffffffffffff

UnrealEditor_Engine!UEngine::GetWorldFromContextObject() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\UnrealEngine.cpp:11383]
UnrealEditor_OnlineSubsystemUtils!FOnlineSubsystemBPCallHelper::FOnlineSubsystemBPCallHelper() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemUtils\Source\OnlineSubsystemUtils\Private\OnlineSubsystemUtils.cpp:799]
UnrealEditor_OnlineSubsystemUtils!UFindSessionsCallbackProxy::OnCompleted() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemUtils\Source\OnlineSubsystemUtils\Private\FindSessionsCallbackProxy.cpp:65]
UnrealEditor_OnlineSubsystemUtils!TBaseUObjectMethodDelegateInstance<0,UFindSessionsCallbackProxy,void __cdecl(bool),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:611]
UnrealEditor_OnlineSubsystemNull!TMulticastDelegate<void __cdecl(bool),FDefaultDelegateUserPolicy>::Broadcast() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:955]
UnrealEditor_OnlineSubsystemNull!TBaseRawMethodDelegateInstance<0,FOnlineSessionNull,void __cdecl(void),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:469]
UnrealEditor_OnlineSubsystem!TMulticastDelegate<void __cdecl(void),FDefaultDelegateUserPolicy>::Broadcast() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:955]
UnrealEditor_OnlineSubsystem!FLANSession::Tick() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystem\Source\Private\LANBeacon.cpp:305]
UnrealEditor_OnlineSubsystemNull!FOnlineSessionNull::Tick() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemNull\Source\Private\OnlineSessionInterfaceNull.cpp:961]
UnrealEditor_OnlineSubsystemNull!FOnlineSubsystemNull::Tick() [D:\build++UE5\Sync\Engine\Plugins\Online\OnlineSubsystemNull\Source\Private\OnlineSubsystemNull.cpp:178]
UnrealEditor_Core!FTicker::Tick() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Private\Containers\Ticker.cpp:95]
UnrealEditor!FEngineLoop::Tick() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5246]
UnrealEditor!GuardedMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:171]
UnrealEditor!GuardedMainWrapper() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:137]
UnrealEditor!WinMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:268]
UnrealEditor!__scrt_common_main_seh() [d:\agent_work\5\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll

I reinstalled UE5, changed the project folder location, I even tried to set up EOS and Steam SDK (but I really need to understand it more first) all with no avail. Any help with this and/or trying to migrate the hours of content of this project back to 4.26 (preferably), I’d appreciated.

Thanks in advance and please excuse any spelling mistakes english is my second language, I’m here - if needed - to clarify anything that didn’t come out clear enough.

For any future reference: I had some corrupted files. Deleted them, tried to reconvert it to 5EA again and then it worked. It is still working now (sometimes it still crashes, but eventually opens the project), but now it shows some weird behavior.:

In PIE Listen Server net mode, Server would perform normally while Clients won’t receive most of keyboard, mouse or gamepad input. The inputs I could confirm to be received is the mouse and gamepad right analog (client normally move the camera). The left analog stick from my gamepad also works, but client still unable to used the keyboard WASD.

Just resolved the input issue: there was a "Any key " node consuming input on the Player Controller. Always check your controller, kids.