Early in the fig cutting rooting process this may happen to you. It may be time to change something because either 1 of 3 things are occurring:
1. Your cutting is rotting in the soil due to improper soil moisture and a lack of oxygen.
2. Improper environment. Fig trees metabolically perform their best at 78F. The same goes for rooting. Stay within the 75-80F range if you can. Add a heat mat if you're missing some degrees of temperature.
3. Your lighting is inadequate. Most likely they are not positioned properly or running long enough. I run mine for 16 hours a day and they're positioned 4 inches away from the leaves. 1-3 FT for LEDS.
Overall, be patient. You can expect most cuttings to show activity after 3-6 weeks. They may also need some time to put out some roots before continuing growth. If 1-3 are correct, there is no worry.
Check out my latest video for my thoughts on the subject and my current results: