The error was found in a bonus feature, called a progressive jackpot, in the online slot-machine game the Wizard of Odds.
Spokeswoman Susan Dolinski says an error message appeared when players hit the jackpot and they didn't get paid.
The corporation says it removed the game from its PlayNow.com website June 10, conducted a review, discovered the error and identified nine players who had won the progressive jackpots totalling nearly $1.1 million.
Dolinski says it will also reimburse others who played the game and experienced a loss between July 16, 2014 and June 11, 2015, while those who won money will still get to keep their winnings.
The lottery corporation says it has made $109 million in gross revenue in 2014 and 2015 through its gaming website. (The Canadian Press, CHNL)
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