Someone who heard the Prophet ﷺ reported that he said, "Whoever is prompted at the moment of death to say, 'There is no god but Allah,' will enter Paradise."
حدثنا حسن بن موسى قال حدثنا حماد بن سلمة عن عطاء بن السائب
حدثني من سمع النبي ﷺ يقول من لقن عند الموت لا إله إلا الله دخل الجنة
Its chain is hasan, and what brought it down below sahih was Zazan and Ata together, for the hadith would be sahih if either of them had been narrated from alone by a reliable, precise reporter. Zazan is trustworthy but there is some discussion about his memory, so his hadith is sahih if it is narrated from him by someone better and more precise than him. But Ata is no better off than Zazan.As for Haythami, he cited the hadith at 2/322 and said, "It contains Ata bin Saaib, who became confused in his later years."