Space stuck on "Starting" indefinitely with completely clean startup log (Gradio 6.6.0, SSR disabled)

Space: alvarocas/cosmo-emulator (private — happy to share with staff via DM if needed) SDK: gradio, sdk_version: 6.6.0 Hardware: CPU Basic

My Space has been stuck on “Starting…” indefinitely since 06/20/2026. It worked correctly until 06/18/2026, with no changes to the code in between the working and failing runs (later changes were debugging attempts, listed below).

The container logs show a completely clean startup with no exceptions and no further output after the app reaches its ready state:

[EMULATOR] Loading checkpoint: /app/weights/[...].pth
[DATASET] Loaded 256 samples.
[EMULATOR] Simulations available from CosmoDataset: 256
* Running on local URL: http://0.0.0.0:7860
* To create a public link, set `share=True` in `launch()`.

Despite reaching Running on local URL, the Space UI never transitions from “Starting” to “Running”, even after waiting several hours / overnight.

What I’ve already ruled out:

• Disabled experimental SSR explicitly (demo.launch(ssr_mode=False)) — confirmed by the absence of with SSR ⚡ in the log after the change.
• Fixed a non-integer scale value on a gr.Column (Gradio 6 requires int).
• Moved css from the gr.Blocks() constructor to launch() per the Gradio 6 deprecation warning.
• Multiple Factory Rebuilds — same clean log every time, same “Starting” hang.

None of the above changed the outcome.

Has anyone seen this exact pattern recently — clean Python startup, app listening on port 7860, but the Space never reports as Running?

Thanks!