{"record":{"id":"dbb769422886b500","repo":"windmill-labs/windmill","slug":"server-error-text-failed-to-sign-multiplayer","errorCode":null,"errorMessage":"<server error text> || Failed to sign multiplayer session","messagePattern":"<server error text> \\|\\| Failed to sign multiplayer session","errorType":"http","errorClass":null,"httpStatus":null,"severity":"error","filePath":"frontend/src/lib/components/debug/debugUtils.ts","lineNumber":95,"sourceCode":"\n/**\n * Sign a multiplayer session request. Returns a JWT token that the\n * multiplayer server will verify before accepting the WebSocket connection.\n */\nexport async function signMultiplayerRequest(workspace: string): Promise<string> {\n\tif (!workspace) {\n\t\tthrow new Error('No workspace selected')\n\t}\n\n\tconst response = await fetch(`/api/w/${workspace}/debug/sign_multiplayer`, {\n\t\tmethod: 'POST',\n\t\theaders: { 'Content-Type': 'application/json' },\n\t\tbody: JSON.stringify({})\n\t})\n\n\tif (!response.ok) {\n\t\tconst errorText = await response.text()\n\t\tthrow new Error(errorText || 'Failed to sign multiplayer session')\n\t}\n\n\tconst data: { token: string } = await response.json()\n\treturn data.token\n}\n\n/**\n * Get a user-friendly error message for debug errors\n */\nexport function getDebugErrorMessage(error: unknown): string {\n\tconst message = error instanceof Error ? error.message : String(error)\n\n\t// Handle token verification errors from debugger\n\tif (message.includes('Token verification failed') || message.includes('Debug token required')) {\n\t\tif (message.includes('expired')) {\n\t\t\treturn 'Debug session expired. Please try again.'\n\t\t}\n\t\tif (message.includes('Invalid JWT signature')) {","sourceCodeStart":77,"sourceCodeEnd":113,"githubUrl":"https://github.com/windmill-labs/windmill/blob/e474e8803ce2ff5c2df09a58dab51d45f5c922ca/frontend/src/lib/components/debug/debugUtils.ts#L77-L113","documentation":"signMultiplayerRequest's failure path: any non-OK response from POST /api/w/{workspace}/debug/sign_multiplayer causes the server's error text — or the fallback 'Failed to sign multiplayer session' when the body is empty — to be thrown. The multiplayer server will subsequently reject the WebSocket connection without a valid JWT, so collaboration cannot start.","triggerScenarios":"Non-2xx from /debug/sign_multiplayer: 401/403 (expired/insufficient token), 404 (workspace not found or route absent on this backend version), 5xx from backend or proxy, or empty error body triggering the fallback.","commonSituations":"Session token expired while the editor stayed open; user lacking multiplayer entitlement (EE feature); backend version without the sign_multiplayer route; reverse proxy 502/503 during deploys.","solutions":["Read the thrown text / network status to identify the rejection; for 401/403 refresh the login or permissions.","Confirm the backend build supports sign_multiplayer (EE/multiplayer enabled) — a 404 means the route is absent.","Retry after transient 5xx/proxy errors; check backend logs if persistent.","Verify the workspace id exists and the user is a member."],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"try { const token = await signMultiplayerRequest(ws) } catch (e) { disableCollaboration((e as Error).message); }","preventionTips":["Treat sign failure as 'collaboration unavailable' and degrade gracefully instead of crashing.","Retry with backoff only on 5xx/network errors, not on 401/403.","Re-sign when the underlying auth token refreshes."],"tags":["multiplayer","network","http","authorization"],"backgroundTag":"http-request-failed","analyzedSha":"e474e8803ce2ff5c2df09a58dab51d45f5c922ca","analyzedAt":"2026-09-03T12:38:19.024Z","contentChangedAt":"2026-09-03T12:38:19.024Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}