Looks like its dry or you damaged the roots while transplanting.
Make sure your lights are high enough above the plant. Remember the roots for that plant do not fill the bucket, so although the soil looks wet all over, the root zone may be dry. Only water the small area around the base of the plant, where it meets the soil. Then, the hardest part.....WAIT!!! LOL
In soil it is going to take a few days for a response, but if its a issue of being dry, you should see the plant perk back up after an hour or two.