Coe was sentenced in 2011 after pleading guilty in U.S. District Court to conspiracy to commit wire fraud.
Prosecutors said the scam targeted senior citizens around the country, telling them they had won cash prizes but had to pay taxes and fees to claim the money.
Prosecutors said the scam netted tens of thousands of dollars from victims in California, Illinois, Kansas, Maryland, Michigan, Mississippi, New Hampshire and Vermont. Some of the money made its way to Mississippi.
According to court records, Coe was the seventh person to plead guilty in the case.
Coe did not challenge his guilty plea in his appeal. Instead, he argued that his sentence was too harsh.
A three-judge panel of the 5th U.S. Circuit Court of Appeals on Tuesday ruled against Coe.
U.S. District Judge Sharion Aycock sentenced Coe to 14 years and seven months in prison.
"Coe has not demonstrated error, plain or otherwise, with respect to his argument that the court imposed his sentence on the basis of clearly erroneous facts," the three-judge panel said.
Authorities said the scam began with a call to tell victims they had won a large cash prize. The victims then were told to wire money to cover fees and taxes on the supposed prize. The money was often shifted around the country by members of the scheme.
The scam usually got about $2,800 to $2,900 per payment; five people paid more than once, according to a 13-count indictment. A woman in California allegedly sent more than $12,000 in three payments.