Hi there, this is an overwatering problem. You can see this from the puffy space between the veins of the leafs . When you overwater , the soil keeps humid too long so it develops water mold which attacks the roots and when you have root problems you can see downwards pointing curling on the leaves. So what you want to do to fix this is water less and less often, try using the lifting pot method to never overwater again :
www.youtube.com/watch . The next part is to fix the infected roots. For this stop feeding anything except the microvita at half dosage for 10 days or 2 weeks and it will stabilize the soil and the root zone. Microvita has special bacteria inside to digest the problem roots so that they can grow back healthy. So that's quite a common problem and an easy fix. Hope this helps ! 🚀