Troubleshooting
Common issues and production fixes.
Matrix
| Symptom | Likely cause | Fix |
|---|---|---|
ValidationError on filename | Missing .xlsx/.csv/.txt | Use valid extension or disable strict extension policy |
| Empty file in server | Using download mode in backend | Use mode: "buffer" |
| Formula appears as text | Value sanitization applied | Use a formula column (formula) intentionally |
| High memory use | Huge single-sheet export | Split by sheets and benchmark |
| Menu not styled | Headless mode enabled | Remove unstyled or provide your own classes |