Liquidations can only occur when you take on leverage/ borrow funds to take on large positions.
Liquidation occurs when your margin ratio falls below the required margin maintenance. In other words, the amount of collateral that you have and the value of your positions start go below a certain threshold.
You can view your margin ratio on your Portfolio tab.
The margin ratio is calculated as follow:
margin ratio = (total deposits + value of positions) / borrowed amount
The current margin maintenance is set to 110% or:
margin maintenance = 1.10
When your margin ratio falls below the margin maintenance, your account runs the risk of being marked for full liquidation, during which time you will not be able to deposit, withdraw or place trades.
If you are unable to deposit, withdraw or place any trades, and your margin ratio is below 1.10, it is likely that you are under liquidation. Simply wait a few seconds and refresh.