What does this error mean?
The Error placing buy order error means your bot tried to place an order on BingX, but the order did not meet the minimum trade requirements. BingX requires a minimum trade amount of 5 USD, but the minimum trade quantity for a specific cryptocurrency can be higher than that. This means your order value can be above 5 USD and still get rejected if the required coin quantity isn't met.
The screenshot below shows an example: the minimum required quantity was 701 LAI, but the bot tried to place an order for only 472.1 LAI.
What you can do
You have two options:
Do nothing. Your bot will not be able to buy this coin as long as the order amount stays below the minimum. The error will keep appearing.
Increase your quote currency amount. Go to your bot's settings and increase the amount of quote currency per order. This ensures your bot meets the minimum trade quantity on BingX and can place the order.
Verify the issue is resolved
After increasing your quote currency amount, check your bot's log. If the fix worked, the Error placing buy order error will no longer appear for this coin.