It worked, then stopped overnight

If automation only fails while you are asleep, the cause is almost always the machine rather than the strategy - and the machine has a small number of ways to go quiet.

Windows restarted itself

An automatic update reboots the machine, and MetaTrader does not come back on its own unless you have told it to. Set active hours to cover the whole trading week, or disable automatic restarts entirely on a machine whose only job is to stay running.

The machine slept

Set both screen and sleep to Never. A sleeping machine holds no connection, and a dropped connection means every command sent during it is simply gone - bridges do not queue and replay.

The terminal lost its connection

Check the connection indicator in the bottom-right of MetaTrader. A dropped session can look identical to a running one at a glance. Enable the terminal's own auto-start and log-in so a reboot restores it without you.

Confirm it survives a reboot

The only real test: restart the machine deliberately, walk away, and come back to check that the terminal is open, logged in, the EA is attached, and Algo Trading is green. If any of those needs a human, the setup is not yet hands-free.