There is an unknown (potentially weak) narrator between Asim and Umar and a break in the chain between Umar and Salman so its authenticity is questionable.
Ibn Kathir in البداية والنهاية comments on this tradition as follows:
هكذا وقع في هذه الرواية. وفيها رجل مبهم وهو شيخ عاصم بن عمر بن قتادة.
وقد قيل إنه الحسن ابن عمارة ثم هو منقطع بل معضل بين عمر بن عبد العزيز
وسلمان رضي الله عنه. قوله لئن كنت صدقتني يا سلمان لقد لقيت عيسى بن
مريم غريب جدا بل منكر. فإن الفترة أقل ما قيل فيها أنها أربعمائة سنة،
وقيل ستمائة سنة بالشمسية، وسلمان أكثر ما قيل أنه عاش ثلاثمائة سنة
وخمسين سنة. وحكى العباس ابن يزيد البحراني إجماع مشايخه على أنه عاش
مائتين وخمسين سنة. واختلفوا فيما زاد إلى ثلاثمائة وخمسين سنة والله
أعلم. والظاهر أنه قال لقد لقيت وصى عيسى بن مريم فهذا ممكن بالصواب.
وقال السهيلي: الرجل المبهم هو الحسن بن عمارة وهو ضعيف وإن صح لم يكن
فيه نكارة. لأن ابن جرير ذكر أن المسيح نزل من السماء بعد ما رفع فوجد
أمه وامرأة أخرى يبكيان عند جذع المصلوب فأخبرهما أنه لم يقتل وبعث
الحواريين بعد ذلك. قال وإذا جاز نزوله مرة جاز نزوله مرارا ثم يكون
نزوله الظاهر حين يكسر الصليب ويقتل الخنزير ويتزوج حينئذ امرأة من بني
جذام وإذا مات دفن في حجرة روضة رسول الله صلى الله عليه وسلم.
English translation by Trevor LeGassick
That, then, is how this anecdote is worded. There is (in its chain of
authorities) one man of questionable reliability {unknown}, he being Sheikh { teacher of; from whom narrates}
'Asim b. Umar b. Qatada. That link is also said to have been al-Hasan
b. Umara. The tradition is also missing a link, indeed untraceable,
between Umar b. 'Abd al-'Aziz and Salman, may God be pleased with him.
As for his words, "If you have told me the truth, O Salman, you have
met Jesus son of Mary," these are very strange, if not unacceptable.
For the period involved must, by all accounts, be one of 400 years,
perhaps even 600 years by the solar calendar. The longest anyone
suggests that Salman lived is some 350 years. Al-Abbas b. Yazid
al-Bahrani related that the consensus of his elders was that he lived
for 250 years; they differed as to whether it could have been as much
as 350 years. But God knows best. And it seems that he was saying,
"You met a (good) follower of Jesus, son of Mary." And that could well
be true.
Al-Suhayli stated, "The man of questionable reliability (in the above
chain of authorities) is al-Hasan b. Umara, a weak authority. But if
he was correct, then there is nothing unacceptable about it. Because
Ibn Jarir related that Jesus came down again to earth after he had
been resurrected { raised up } and that he found his mother and another woman
weeping at the cross of the crucified man. Jesus told them that he had
not been killed, and after that he sent his disciples." He went on:
"And if it is possible that he came down once, then it is possible he
did so many times. Moreover there is his evident return when he broke {will break}
the cross and killed {will kill} the pig and thereafter married {marry} a woman of Banu
Jidham and finally was {be} buried in a chamber of the grave (usually
referred to as the garden) of the Messenger of God (SAAS)."
Note that this translation contains several errors I've added some corrections in {}.
