Use SLOG3 Licensed Transform
After you've got SLOG3 License, you can use the LUT which includes SLOG3 OOTF in licensed LLUTBOX.
If you are setting non-licensed LUTBOX, you can select SLOG3 OOTF but you can not send the LUT which includes SLOG3 OOTF.
You can save the transform which contains SLOG3 OOTF, but you can not export it to LUT file even if you had a license. You can only use it by sending LUT to the