microsoft/playwright · error · Error

Failed to connect to MCP relay: ${error.message}

Error message

Failed to connect to MCP relay: ${error.message}

What it means

Error "Failed to connect to MCP relay: ${error.message}" thrown in microsoft/playwright.

Source

Thrown at packages/extension/src/pendingConnection.ts:53

      return undefined;
    this._map.delete(selectorTabId);
    return openRelayConnection(mcpRelayUrl);
  }
}

async function openRelayConnection(mcpRelayUrl: string): Promise<RelayConnection> {
  try {
    const socket = new WebSocket(mcpRelayUrl);
    await new Promise<void>((resolve, reject) => {
      socket.onopen = () => resolve();
      socket.onerror = () => reject(new Error('WebSocket error'));
      setTimeout(() => reject(new Error('Connection timeout')), 5000);
    });
    return new RelayConnection(socket);
  } catch (error: any) {
    const message = `Failed to connect to MCP relay: ${error.message}`;
    debugLog(message);
    throw new Error(message);
  }
}

View on GitHub (pinned to c8fc3bf8d3)

When it happens

Trigger: Thrown at packages/extension/src/pendingConnection.ts:53 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/playwright@c8fc3bf8d3 (2026-08-12). Data as JSON: /api/errors/180299c7ba63b16f. Report an issue: GitHub.