If you could copy/paste this support ticket, you’d get a more accurate response.
Strain; Type, Bag seed, or NA
Soil in pots, Hydroponic, or Coco?
PH of runoff or solution in reservoir?
What is strength of nutrient mix? EC, or TDS
Indoor or Outdoor
Light system, size?
Temps; Day, Night
Humidity; Day, Night
Ventilation system; Yes, No, Size
AC, Humidifier, De-humidifier,
Co2; Yes, No
Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help
Welcome to the community ! along with the support ticket I would also post a picture of the whole plant. Lot of Growers here to help you and share knowledge good luck.
Looks like phosphorus deficiency.