I created a monorepo project in Firebase Studio, but I am facing a persistent issue where the development port keeps getting automatically disconnected.
Most of the time, the platform does not open at all because the port always remains in a “disconnected” state. Even when it connects briefly, it disconnects again after a few seconds.
The issue becomes more frequent when dynamic page titles update, runtime errors occur, or when the dev server restarts internally. These events seem to break the port forwarding connection.
The exact error message shown is:
“Unable to forward your request to a backend.
Couldn’t connect to a server on port 9006. Ensure you have selected the correct port with a HTTP server running on it.”
This error indicates that Firebase Studio’s port forwarding layer cannot maintain a stable connection with the local HTTP server running inside the workspace.
In a monorepo setup, multiple services or packages may start, stop, or rebind ports dynamically. When the main dev server restarts or crashes temporarily, Firebase Studio loses the active backend reference.
Once the forwarding layer loses that reference, it does not always recover automatically, even if the server comes back up on the same port.
Because of this, the platform UI keeps showing the port as disconnected, and requests never reach the backend.
In many cases, the server is actually running correctly, but Firebase Studio fails to re-attach to it.
This makes local development unreliable, especially for large monorepos where hot reloads, crashes, or dynamic rebuilds happen frequently.
The problem appears to be related to unstable port forwarding rather than application-level code issues.
As a result, development becomes blocked with a permanent “Unable to forward your request to a backend” error.
