Why the connection to the MySql database is disconnected after 20 seconds “Connection must be valid and open”

Why the connection to the MySql database is disconnected after 20 seconds "Connection must be valid and open" If I do not do this time in the program. As I learned that the timeout on the hosting is 20 seconds. Then how to maintain the connection?

private async Task LoadStudentsAsync1() { string connStr = "Server = sql221.maidf.eu; Database = u983222dfa; Uid = u983222asd; Pwd = themdf;"; // строка подключения к БД sqlConnection = new MySqlConnection(connStr); // создаём объект для подключения к БД await sqlConnection.OpenAsync(); // устанавливаем соединение с БД await LoadStudentsAsync(); }