How sound is the Hadith: "Whoever is granted supplication will not be deprived of an answer"?

This tradition (athar) has been narrated with different wordings and narrations, some of which are Marfu‘ (traced back to the Prophet) and some Mawquf (traced back to a Companion), but none of them are authentic. All its narrations are weak, and their chains of transmission contain unknown narrators. Al-Bayhaqi and others have deemed them weak.