The SPFL have found Cove Rangers guilty of listing an ineligible player on the teamsheet against Alloa.
The club have been fined £2,000, with 75 per cent of that suspended until December 31, 2017.
Lewis Dunbar was an unused substitute in the Betfred Cup game with the Championship club last Tuesday.
But Cove had not properly registered the 18-year-old for the match, which finished 4-0 to Alloa.
The SPFL decided the Highland League club did not “gain any sporting advantage” and fined the club.
Cove have also been warned about their future conduct in relation to player registration.
Club secretary Duncan Little acknowledged the mistake and accepted the decision.
He said: “It was a little minor error, just one of those things.
“At this stage of the season, we slipped up, we’ve got no problem with it.”
League One side Stranraer were also hit with a fine for the same offence.
Nathan Brown was not properly registered for their tie against Annan, which they won 2-1.