"During the monitoring of the votes submitted by the Egyptian Football Association (EFA) on August 15, it was remarked that the signatures on the voting forms were in capital letters and thus seemed not valid (not authentic)," said FIFA.
Other contenders for the award were Dutch hopefuls Frenkie de Jong and Matthijs de Ligt, Eden Hazard, Harry Kane and Kylian Mbappe.
Nominees for Best FIFA Women's Coach and Player were also announced on Tuesday.
Ronaldo won the inaugural Best FIFA men's player of the year award last year following the end of a six-year merger between the FIFA honour and France Football's Ballon D'Or.
Cristiano Ronaldo on Monday lifted his fifth Best FIFA Men's Player award in London.
Real Madrid and Portugal all-time top scorer Ronaldo is the favourite to win the award's second edition.
