While the postponing of prayers is generally disliked, ʿIshāʾ is one exception. Sheikh Muḥammad ibn Ṣāliḥ al-Uthaimīn (رحمه الله) was asked:
"What is the ruling on delaying the ʿIshāʾ prayer until a late hour?"
He (رحمه الله) then responded:
"It is better for the ʿIshāʾ prayer to be delayed to its later time. The more it is delayed, the better, unless it be for a man, because if a man delays it, he misses the congregational prayer, and it is not permissible for him to delay it and miss the congregational prayer. As for women in their houses, the more they delay the ʿIshāʾ prayer, the better it is for them, but they should not delay it past midnight."
And you shouldn't delay the prayer past midnight due to the fact that after midnight is the next day, thus it counts as missing the prayer entirely and must be made up.
The Prophet (ﷺ) said:
May Allāh have abundunt mercy upon Sheikh Muḥammad ibn Ṣāliḥ al-Uthaimīn, and may Allāh bless you, and shukran.
Sources :
The fatwā is taken from Fatāwā Islāmīyah vol no. 2, page no. 239.
1. at-Tirmidhī 167