Your account(s) have a high amount of active symbols which can cause the terminal to freeze/crash during increased volatility.
This is a well-known issue to MT4 being a 15+year-old application and not being able to cope with the volume of price changes it is fed by modern markets.
On our platform, you may see this affect your experience in 2 ways;
To reduce the risk of this issue, you should reduce the amount of active symbols for the account(s). To do this, go to Configurator then Account settings for the account, then Disable Symbols sub-menu. You then need to deselect/untick the symbols you do not trade on the account. Once complete, click Update and you will see the new counts of enabled/disabled symbols. You should aim for around 50 active symbols or less.