What is the ruling on unintentionally forgetting the Maghrib and Isha prayers on one's wedding day, and is expiation due for them?

The sister must make up the prayers she missed. There is no expiation or sin upon her if she missed them due to forgetfulness and unintentionally, because Allah Almighty does not hold His servants accountable for forgetfulness and sleep, as stated in His saying: "Our Lord, do not hold us accountable if we forget or make a mistake," and the saying of the Prophet, peace and blessings be upon him: "Whoever forgets a prayer or sleeps through it, let him pray it when he remembers it. There is no expiation for it except that."