Your issue is very straightforward—you don’t actually have enough usable balance to buy anything.
From your screenshot (on Spot trading):
Available balance: 0.00000361 USDT
Max Buy: 0 NIGHT
That amount is essentially zero in trading terms. Even the cheapest order on the NIGHT/USDT pair needs a minimum value (usually around 5–10 USDT on Binance).
Why the Buy button isn’t working
Your balance is too small to meet the minimum order size
So Binance disables the trade → shows Max Buy = 0
How to fix it ✅
You need to add more USDT to your Spot Wallet:
Option 1: Transfer (if you already have funds)
Go to Wallet → Funding / Futures / Earn
Tap Transfer
Move USDT → Spot Wallet
Option 2: Deposit
Tap Deposit
Choose USDT
Send from another wallet/exchange
Option 3: Buy USDT
Use P2P or card purchase inside Binance
Important tip ⚠️
Even if you add a small amount like 1 USDT, it still may not work due to minimum trade limits. Aim for:
At least 5–10 USDT to trade comfortably
If you want, I can guide you step-by-step based on what you currently have (P2P, bank, Easypaisa, JazzCash, etc.).