# Troubleshooting

## WASM module fails to load

- Confirm browser supports WebAssembly (any browser from 2018+).
- Hard-refresh (Ctrl-Shift-R) to bypass stale cache.
- DevTools → Network: verify `gdbs_web_client_bg.wasm` returns 200.
- If 404: check `pkg/` exists under `wwwroot/` — a partial deploy can omit it.

## GPU adapter unavailable

WebGPU requires:

- Chrome 113+, Edge 113+, Firefox Nightly with `dom.webgpu.enabled`.
- `chrome://gpu` shows "WebGPU: Hardware accelerated".
- Linux: Vulkan 1.2+ driver.

Without GPU, the standard module tabs still work — only the heavy validation grids (51² ballooning, 257² Soloviev) need GPU acceleration, and even those have CPU fallback paths.

## License gating still showing after I paid

- Sign out and back in — forces JWT refresh.
- Wait 60 s for the Stripe webhook to land.
- Still gated after 5 min? Open a P2 ticket; we resync manually.

## Numerical result looks wrong

1. Bump precision tier to 2 or 3 (Relational Depth slider).
2. Run the **Convergence** tab with your same inputs. If `rel_error` at finest grid > 1%, the problem is under-resolved.
3. Run the **Validation Suite** for the closest canonical reference. If we match canonical but disagree with your input, the input is the likely issue.

## My computation took > 3 seconds

That's our service budget. Open a ticket with the exact inputs — we'll investigate the slow path. Common causes:

- n_radial > 512 (the trapezoid sum gets quadratic).
- Ballooning n_theta > 801 (tridiagonal scales linearly but inverse iteration converges slower at very high resolution).
- EFIT file > 5 MB (large grid round-trip).

## Export results for a paper

- Pro tier: Export tab — CSV, JSON, BibTeX bundle.
- Free tier: copy the result table directly from the UI.

## Citing GDBS

See [Citing GDBS](#docs:citing-gdbs).