Insufficient funds means the margin requirement to open the trade is higher than your account balance. Some questions what is the leverage on your account and what is the highest leverage your broker allows for gold?
For instance is your broker allows up to 1:1000 leverage on gold but your trading account leverage is set to 1:400, you can go to your client area and increase the account leverage to 1:1000. This should reduce the margin requirement required to open the trade.