Saheeh (sound) hadeeths, Dought & Clear, - * Soundness of the hadeeth, “Whoever recites Aayat al-Kursiy after every prayer

What do you say about the hadeeth of Abu Umaamah, that the Prophet
(peace and blessings of Allaah be upon him) said: "Whoever recites
Aayat al-Kursiy after every prescribed prayer is not prevented from
entering Paradise by anything except death"?
Praise be to Allaah.
This hadeeth was narrated by al-Nasaa'i in'Aml al-Yawm wa'l-Laylah, by
Ibn al-'Sunni in'Aml al-Yawm wa'l-Laylah, by al-Tabaraani
inal-Kabeerand by others, via Muhammad ibn Humayr from Muhammad ibn
Ziyaad al-Alhaani from Abu Umaamah (may Allaah be pleased with him)
from the Prophet (peace and blessings of Allaah be upon him). There is
nothing wrong with its isnaad, and it was classed as saheeh by Ibn
Hibbaan inKitaab al-Salaahand by al-Mundhiri, Ibn 'Abd al-Haadi and
Ibn Katheer.
It was extreme on the part of Ibn al-Jaawzi to include it in his
bookal-Mawdoo'aat("fabricated reports"), and this is not to be
accepted.
The hadeeth was narrated only by Muhammad ibn Humayr from al-Alhaani.
This hadeeth may be classified as ma'lool (defective), especially as
al-Qasawi (may Allaah have mercy on him) said: Muhammad ibn Humayr is
not qawiy (strong).
Ibn al-Ma'een disagreed with him and said that he [Muhammad ibn
Humayr] was thiqah (trustworthy). Imaam Ahmad said, I do not know
anything but good about him. Al-Nasaa'i said: there is nothing wrong
with him.
The isnaad of this hadeeth is jayyid, but it is not saheeh. But
reports of this kind may be accepted for a number of reasons:
1. Imaam al-Nasaa'i (may Allaah have mercy on him) narrated it and
did not regard it is ma'lool (defective); he narrated it in
hisMukhtaarahand classed it as saheeh.
2. The hadeeth does not deal with any major ruling of sharee'ah.
3. If asadooq(truthful narrator) is the only one to narrate a
hadeeth, it may be accepted if there is evidence that his narration
was of good quality. The fact that Muhammad ibn Humayr was the only
one to narrate it is a case in point, but there is corroborating
evidence in the ahaadeeth of al-Mugheerah ibn Shu'bah, Abu Mas'ood and
'Ali ibn Abi Taalib, even though none of those reports are saheeh. And
Allaah knows best.