JoAnn and Gaetan Champagne claimed their LottoMax prize at the headquarters of the Ontario Lottery and Gaming Commission in Toronto this week and learned of the delay, The Globe and Mail reported.
The couple ran a convenience store until October in their hometown of Hawkesbury, near Ottawa, where they also sold lottery tickets.
In 2009, the gaming commission known as OLG instituted a "No Play at Work" policy in which ticket sellers are not allowed to purchase or even check their own tickets where they work.
Even though the couple sold their store, JoAnn continued working there part-time and was an employee when the ticket was purchased at another retail location, the newspaper said.
The big prize will be investigated both by the OLG and the Ontario Alcohol and Gaming Commission of Ontario, the Toronto Star reported.
The couple were aware there would be follow-up investigations, the Globe said.