Your soil PH could be out of whack if it's too heavy in coco or peat.
The easiest route to success is a bagged soil with forest products already in it, and an all in one bottled nutrient like Floranova after 4 weeks once the soil starts depleting.
No Cal Mag necessary.
Some beneficials like Recharge or Mykos are good too, but you can grow without it.
I'm sorry I can't give you much help for your current situation other than don't give it Calmag and stop feeding it for a bit.
I don't think it's hungry from neglect. I think it's locked out.