What is the authenticity of the Hadith: "O Allah, reward Muhammad, peace and blessings be upon him, with what he is worthy of"?

This hadith was narrated with a similar wording, but it is not authentically attributed to the Prophet, peace and blessings be upon him. Al-Haythami said in Al-Majma': "From Ibn 'Abbas, he said: The Messenger of Allah, peace and blessings be upon him, said: 'Whoever says, "May Allah reward Muhammad on our behalf what he is worthy of," will exhaust seventy scribes for a thousand mornings.' Narrated by Al-Tabarani in Al-Kabeer and Al-Awsat, and it contains Hani' ibn Al-Mutawakkil, who is weak."