Simonsen was banned for two matches, one of which was suspended, after admitting to gambling on a total of 55 matches over a 12-month period.
The SFA’s compliance officer, Tony McGlennan, challenged that decision, believing the “sanction imposed was unduly lenient”.
However, that appears to have been unsuccessful with Pro Legal Group tweeting: “SFA Appeal against Steve Simonsen suspension fails.”
Simonsen, 35, told a disciplinary hearing he believed the SFA followed the same rules as its English counterparts when he moved to Scotland in 2013.
In England, players had been forbidden only from betting on matches involving their own teams and competitions in which they were involved, but those rules have now been changed to follow the Scottish example.
Simonsen did not bet on any games relating to his club’s competitions and was banned when an SFA-convened judicial panel met on February 12.
He missed the club’s February 13 clash with Hibernian but has not played since after dropping down Gers’ goalkeeping pecking order.