[fredrikbernholm]

A cookie-authenticated client that negotiates through an Azure SignalR redirect can connect once but fail every automatic reconnect. The cached bearer token from the service redirect survives the next HttpConnection.start(), so the client sends that service token to the original application's negotiate endpoint even though no application accessTokenFactory is configured.

Clear the cached HTTP token when a connection starts, alongside restoring the application's token factory. The original endpoint can then use cookie authentication again, and the redirected service receives its newly negotiated token.

The regression starts, stops and restarts a connection with a negotiate redirect, checking the Authorization header at both endpoints. It fails on current main before the fix. All 84 HttpConnection tests pass with the fix, and the touched test file passes ESLint.

Also reproduced against a live Azure SignalR deployment with client 9.0.6: the initial connection and group subscription succeeded, but terminating the WebSocket caused subsequent application negotiations to return 404 with the service bearer token attached. Clearing the cache restored negotiation, automatic reconnect, group rejoining and backend push delivery. A released-client regression also fails before the fix and passes afterward.

[dotnet-policy-service]

Thanks for your PR, @fredrikbernholm. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[fredrikbernholm]

Replaced with bug report #69917 so the issue can be triaged before proposing a change.