Super League club Salford Red Devils have lost their appeal against a six-point deduction imposed for breaching salary cap regulations.
An independent Rugby Football League tribunal ruled on charges brought in April.
And an independent body has upheld the verdict, which also saw Salford fined £5,000 for "seeking to avoid declaring payments" to one player and "non-declaration of benefits" to two others.
Salford remain ninth in the table.
The Red Devils are five points behind eighth-placed Castleford and must win their next three matches, starting at Warrington on Thursday, to stand any chance of finishing in the top eight.
Following Thursday's announcement, Koukash said: "It's very disappointing.
"Although we demonstrated that we haven't broken the salary cap, and in many ways the RFL has accepted that, the centre point is that I broke the operational rules, which is not declaring three payments in 2013, to which I hold my hand up."
A spokesperson for the RFL added: "The decision today from [independent body] Sports Resolutions clearly shows that the RFL disciplinary process is robust and fair.
"It is of utmost importance that clubs adhere to the salary cap and that if they are found to have broken it they are held to account.
"As we have previously stated and agreed we see this decision as final and binding and hope all parties involved can now focus on the rest of the season."