are you trying to use 100% Of your balance?
If you get this error is because you don't have funds.
As i said this is an error from the exchange not from CAT
no you always have to reduce to ~half of your funds, sometimes much more reducing
if you take 100% you have always a rounding error (perhaps fees are not included...)
These are rule inside the exchange.
Some exchanges deduct fees AFTER trade, some others BEFORE.
Don't use 100% Of your Balance, can't you use 95%?
And don't forget that if you try to create little orders, CAT (if option is enabled) will adequate the order to the min amount allowed. Maybe this thing is alread happens before you get errors.
It's not easy to give support without any log