Steps to reproduce:

1. Open the attached project
2. Open the Sample Scene
3. Enter Play mode
4. Create a new session with a name of "T1"
5. In the Multiplayer Play Mode window, start a virtual Player
6. In the Virtual Player Game view, enter the session code
7. Press the Join button

Actual results: Player does not join the session and a "SessionException: lobby code 'T1' contains an invalid character '1' (U+0031) at index 1" error is thrown

Expected results: Player joins the session without any errors or warnings

Reproducible with versions: 1.0.0(6000.0.48f1), 1.0.1(6000.1.2f1, 6000.2.0b1)

Can’t test with versions: 2022.3.62f1(MP Widgets package is not available)

Tested on (OS): macOS 15.4.1, Windows 11

Full error message:
*
{quote}SessionException: lobby code 'T1' contains an invalid character '1' (U+0031) at index 1
Unity.Services.Multiplayer.LobbyHandler.JoinLobbyByCodeAsync (System.String lobbyCode, Unity.Services.Lobbies.JoinLobbyByCodeOptions options) (at ./Library/PackageCache/com.unity.services.multiplayer@e9296dd42336/Runtime/Multiplayer/Lobby/LobbyHandler.cs:578)
Unity.Services.Multiplayer.SessionManager.JoinByCodeAsync (System.String sessionCode, Unity.Services.Multiplayer.JoinSessionOptions sessionOptions) (at ./Library/PackageCache/com.unity.services.multiplayer@e9296dd42336/Runtime/Multiplayer/Session/SessionManager.cs:107)
UnityEngine.Debug:LogException(Exception)
Unity.Multiplayer.Widgets.SessionManager:HandleSessionException(SessionException) (at ./Library/PackageCache/com.unity.multiplayer.widgets@a5723a5a90fa/Runtime/Session/Session/SessionManager.cs:155)
Unity.Multiplayer.Widgets.SessionManager:<EnterSession>b__14_0(Exception) (at ./Library/PackageCache/com.unity.multiplayer.widgets@a5723a5a90fa/Runtime/Session/Session/SessionManager.cs:144)
System.AggregateException:Handle(Func`2)
Unity.Multiplayer.Widgets.<EnterSession>d__14:MoveNext() (at ./Library/PackageCache/com.unity.multiplayer.widgets@a5723a5a90fa/Runtime/Session/Session/SessionManager.cs:140)
UnityEngine.UnitySynchronizationContext:ExecuteTasks() (at /Users/bokken/build/output/unity/unity/Runtime/Export/Scripting/UnitySynchronizationContext.cs:110){quote}