Relay disconnects player during loading big scenes.

[AwixStudio]

Description

Relay disconnects player during loading big scenes due to "inactive". This problem exist only in Unity 2021.3 In 2021.2 everything works fine for the same project and the same setup. So it looks like it is definitly somethink wrong in 2021.3.

Reproduce Steps

1. Crete really big scene, which loading in, can take long time
2. Try load scene
3. Player is disconnected due to inactive

Actual Outcome

During loading scene with NetworkSceneManager player gets disconnect and error apear:
Received error message from Relay: player timed out due to inactivity. This could be due to an inappropriate value for reconnectionTimeMS when calling NetworkSettings.WithRelayParameters. Also make sure to schedule NetworkDriver updates frequently to avoid this error.

Expected Outcome

Scenes should be loaded without disconnecting players.

Environment

• OS: Windows 10
• Unity Version: 2021.3.5f1
• Netcode Version: 1.0.0

Additional Context

There is no way to change reconnectionTimeMS because Unity override it to 8 seconds.

[NoelStephensUnity]

@AwixStudio
If you have scene management enabled in your NetworkManager, have you tried increasing the Load Scene Time Out value from 20 to say 60 or higher?

[AwixStudio]

@NoelStephensUnity

I have tried 60, 200, 2000, 20000. Result is still the same "player timed out due to inactivity".

[NoelStephensUnity]

@AwixStudio
Thank you for confirming that first step. This is starting to sound like a bug indeed.
The more information I have the better so if you could provide me with any of the following pieces of information it would greatly help me verify the bug and then we can start looking into a fix.

• Could you provide me with the console log output of the client and server-host from startup to the point where the client times out?
• If you could provide me with a project that includes the scene (or one of a similar size) and the bare minimum scripts you wrote to handle loading, then this would be the fastest/best way for me to verify the issue.
• If that is not possible then:
  • Could you provide high-level details about the scene being loaded:
    • What is its file size
    • How many objects are in the scene
    • How many objects in the scene are "in-scene placed" NetworkObjects?
    • What types of assets are in the scene?
      • I.E. Are you using any form of terrain, terrain streaming, addressables, or any third party tools/packages?
  • Could you provide me with any portions of the scripts that initiate the scene loading
  • Are you testing locally (direct IP/LAN/local loopback on your computer) or through relay?

Sorry you are having issues with your project, and once I have a bit more information I will start to investigate it.

[AwixStudio]

@NoelStephensUnity

Thanks for answear. I will be able provide you console log and info about scene file size, etc... earliest on nearest monday. To dont wasting time, I can answear right now about second question.

Due to project complication level and scale, I am unable to provide you part of project with only scene loading (maybe mentioning the name of our project to better illustrate the scale of the project: https://store.steampowered.com/app/1715280/AirportSim/

But we are open to add you to our github repository with project, so you could debug it, is this posible and okay for you?

[NoelStephensUnity]

It is something I can do that was verified internally and as long as this project is too big to be submitted via the editor (looking at it I am assuming that is the case) then it is not unheard of to grant someone (in this case myself) from Unity temporary access to help determine where the underlying issue might be (SDK bug or potentially a feature that hasn't made it to documentation yet). If we end up having to do this, then we will need to get a mutual NDA prior to me looking over your project. Currently, we have a bunch of pending updates to the documentation that should be getting rolled out as technical writers verify the updates. However, I do know that the Scene Management section has recently been updated and that might provide additional details that might help you with this issue. Particularly if you have already "pre-loaded" a scene or need to exclude a scene from being loaded you can use the scene validation feature.

Let's start with the log files first and maybe I might see something there that won't require looking at the entire project.
Also, can you test to see if 2021.3 works when you are just using direct IP? This will help us determine if this is specific to relay and 2021.3 or just 2021.3 itself.

[AwixStudio]

@NoelStephensUnity

After some investigating, we noticed that this error exist only in editor. In build everything works fine.

So, after entered play mode in editor, we create lobby and then join to game through relay.

We started loading in scenes. We loading (as additive scenes) few scenes in row, we start loading next scenes only when all players (in this example only one player - host) loaded in previous scene. Relay gets disconnect on second scene (Keflavik_enviro.scene, File size: 12MB, In scene placed network objects: 0, Objects types: meshes and terrain(we don't use terrain streaming)). We have cheked other scenes with similar size and effect is the same, so it looks rather like loading time dependent error than scene dependent.

Editor log (of course with censored serial numbers) from editor startup to relay disconnect error:
Editor.log

We use addresables but not before ralay error stage. We have also many other packages like: FMOD, GameCoreScarlet, Vegetation like etc... We don't have any network related packages except unity netcode and it's dependencies to create lobbies with unity services.

We have checked with using direct IP, and everythinkg works fine.

I will describe it to be sure I understood you correctly:
We delated all relay-lobbies staff ->
Change protocol type in unity transport from relay to unity transport ->
NetworkManager.Singleton.StartHost() ->
Load scenes with NetworkManager.Singleton.SceneManager.LoadScene(sceneName, mode) (the same way like with relay connection) ->
Editor loaded in all scenes without any problem and without disconnecting.

[NoelStephensUnity]

@AwixStudio
Ok, so this is starting to sound like a relay issue specific to 2021.3.
To make sure I understand correctly:

1. This only happens when running in the editor, but running as a stand alone build it works fine?
2. This only happens with relay on 2021.3 but it works just fine in the editor 2021.2?
3. You have increased the scene loading timeout in the NetworkManager and that does nothing (relative to the issue)
4. You did try direct IP in 2021.3 and it works just fine in the editor, but always times out when using relay?

I have one last question before I pass this along to our Relay folks:
Have you tried increasing the "Disconnect Timeout MS" value from 30000 (default) to like 120000 (or whatever the average time to load the scene is plus like 5 to 10 seconds)?

If you have, then I will get the relay folks to look into this issue.

[AwixStudio]

@NoelStephensUnity

1. Yes.
2. Yes.
3. Yes.
4. Yes.

I have tried to increase "Disconnect Timeout MS" to 3000000, but it doesn't change anything. I will attach screenshot with my transport setup (after increasing values for test as you asked):