Linux thinks I don't own the game, can't join MP server, single player fine

Problem:

Space Engineers (AppID 244850) launches on Linux but the game thinks I don’t own it. In the game log: Service.OwnsGame: False. Because of that, in-game features are blocked (can't connect to multiplayer servers - in particular one I host on a separate machine). I do own the game: Steam license shows “Space Engineers — Steam Store” purchased 30 Aug 2025 (packageID 28952).

Environment:

OS: Fedora 42 (x86_64)

GPU: NVIDIA GeForce RTX 2060 SUPER (proprietary driver 575.64.5)

Steam client build: 1751405894 (Jun 28, 2025)

Proton tried: 8.0 (stable) and 9.0-203 (Beta)

Reproduces with native Steam and Flatpak Steam.

What happens:

Game starts to main menu. Game log shows I’m online but Service.OwnsGame: False.

Single player works fine, can't connect to multiplayer

Expected:

Game should recognize ownership and allow normal gameplay (workshop/multiplayer/etc.).

What I’ve tried:

Verified files, cleared download cache.

Deleted Proton prefix (compatdata/244850) and re-installed the game.

Switched Proton versions (8.0 stable ↔ 9.0 Beta).

Tested with native Steam and Flatpak (fresh install).

Created a brand-new Linux user and signed in—same result.

Confirmed no network blocker (no Pi-hole).

SELinux audit: no AVC denials (ausearch -m avc -ts recent returns none).

Confirmed Steam overlay/steamclient is injected in later runs (e.g., lsteamclient.dll.so, linux64/steamclient.so present in /proc/<pid>/maps).

Key log snippets:

Game log (latest SpaceEngineers*.log)

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Service.IsActive: True

Service.IsOnline: True

Service.OwnsGame: False

Service.UserId: 76561198025043210

Service.UserName: (redacted)

Service.Branch: default

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Dedicated server logs snippet from trying to connect:

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2025-09-10 03:21:22.308: World request received: [redacted]

2025-09-10 03:21:48.025: Server ValidateAuthTicketResponse (TicketCanceled), Steam ID:[007...210] Owner ID:[007...210]

2025-09-10 03:21:48.028: User left [redacted]

2025-09-10 03:22:03.002: Peer2Peer_ConnectionFailed [007...210], Timeout

2025-09-10 03:22:03.012: User left [007...210]

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