Ofcom says ITV has broken some of the watchdog's regulations with some of its competitions.
The broadcasting watchdog began looking into the broadcaster in August after it said an internal audit found "a small number of individual administrative errors" in six of its premium rate competitions since 2014.
The show's competitions in question included Good Morning Britain, Lorraine, This Morning, Loose Women, Ant and Dec's Saturday Night Takeaway, La Vuelta and X Factor: The Band.
Ofcom's investigation found viewers who had entered competitions with postal votes were excluded from the vote altogether, so therefore had no chance of winning, the Mirror reports.
They said in "all cases, some viewers who participated using the postal entry route had no chance of being selected to win."
An Ofcom spokeswoman said: "Our investigation found that people who entered these competitions by post were excluded from the draw, with no chance of winning.
"ITV failed to follow proper procedures and this led to a clear breach of our rules, which require all broadcast competitions to be conducted fairly."
The broadcaster added: "In all cases, some viewers who participated using the postal entry route had no chance of being selected to win the competition."
The Manchester Evening News has contacted ITV for comment.
