# Microsoft.AspNetCore.SignalR.HubException: Failed to negotiate with the server. The negotiation request timed out after 30 seconds.

- **ID:** `dotnet/signalr-negotiate-timeout`
- **Domain:** dotnet
- **Category:** network_error
- **Verification:** ai_generated
- **Fix Rate:** 75%

## Root Cause

SignalR client fails to complete the negotiation handshake within the default timeout, typically due to network latency, server overload, or firewall blocking the WebSocket upgrade.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 6.0 | active | — | — |
| 7.0 | active | — | — |
| 8.0 | active | — | — |

## Workarounds

1. **Increase the negotiation timeout on the client: in JavaScript, use 'const connection = new signalR.HubConnectionBuilder().withUrl('/hub').configureLogging(signalR.LogLevel.Information).build();' and set 'connection.serverTimeoutInMilliseconds = 60000;' before starting.** (80% success)
   ```
   Increase the negotiation timeout on the client: in JavaScript, use 'const connection = new signalR.HubConnectionBuilder().withUrl('/hub').configureLogging(signalR.LogLevel.Information).build();' and set 'connection.serverTimeoutInMilliseconds = 60000;' before starting.
   ```
2. **Optimize server-side negotiation by reducing the number of transports offered: in Program.cs, use 'app.MapHub<MyHub>("/hub", options => { options.Transports = HttpTransportType.WebSockets | HttpTransportType.ServerSentEvents; });' to skip slow transport negotiation.** (75% success)
   ```
   Optimize server-side negotiation by reducing the number of transports offered: in Program.cs, use 'app.MapHub<MyHub>("/hub", options => { options.Transports = HttpTransportType.WebSockets | HttpTransportType.ServerSentEvents; });' to skip slow transport negotiation.
   ```

## Dead Ends

- **** — Increasing the client timeout alone may mask underlying network issues; the server must also handle long-running negotiations. (60% fail)
- **** — Disabling WebSocket transport forces fallback to long polling, which can degrade performance and still timeout if the server is overloaded. (50% fail)