This means the attempted lot size is less than the symbols minimum defined by the broker.
To avoid it, either increase your multiplier or set force min lot to yes, to round up to the lowest allowed lot size. To increase your multiplier go to Configurator > Trade Copier > Copier Configuration > Risk Settings > Increase Multiplier. To set force min lot go to Configurator > Trade Copier > Copier Configuration > Risk Settings > Set force min lot to "Yes".