Sunan Ibn Majah
923
Daif+3

It was narrated that Thawban said:“The Messenger of Allah (ﷺ) said: ‘No person should lead others in prayer, then supplicate only for himself and not for them. If he does that, he has betrayed them.’”

DaifAl-Albani
DaifMuhammad Fouad Abd al-Baqi