Failure list in 2018

To record down items failed after try out as a reminder for future.

Summary
1) Open Put Option with not aware of the Ex dividend date.

1) on date 14 Jun 2018, i open Put option EX 15 Jun 2018 @ Price 277; but on the day 15 jun 2018, i did not aware it was Ex dividend date. so the gap down since market opening is normal. when open Put position should avoid the Ex dividend date to avoid being exercise and earn premium.