Margin call vs stop-out
A margin call is a warning that equity is approaching the minimum margin requirement. A stop-out is the automatic forced closure of positions when equity falls below the stop-out level, typically 20-50% of used margin.
For MT5 EAs, the relevant number is the stop-out level — most brokers close positions automatically at stop-out without waiting for manual action.
How to avoid it
Size positions so that the maximum theoretical drawdown leaves equity above the stop-out level with a 50-100% buffer. If the EA max DD is -20% and your broker stops out at 20% margin, a $5,000 account running the EA at full size could be margin-called during a max-DD event.