Deontay Wilder will now face the man he took his world heavyweight title from, Bermane Stiverne, in his next title defence.
Luis Ortiz was due to challenge the WBC champion but failed a drugs test, with the governing body then turning down his appeal.
Wilder will now go up against Stiverne, with November 4, at the Barclays Center, Brooklyn, New York, expected to be confirmed.
Stiverne, who was ranked No 1 challenger by the WBC was due to take on Anthony Joshua victim Dominic Breazeale, with the winner to fight Wilder.
The 'Bronze Bomber' took the WBC belt from Stiverne with a unanimous points decision back in January 2015.
Stiverne blamed the loss on hydration issues and called for an immediate rematch, but has only fought once since then, almost two years ago.
The Haitian-born heavyweight known as, B.WARE, remains the only fighter out of 38, not to be knocked out by Wilder.
The WBC said in a statement: "The WBC has concluded the process according to its Clean Boxing Program protocol in the adverse finding of Luis Ortiz.
"An official ruling has been sent to the corresponding parties. The WBC has withdrawn its sanction of the Wilder vs. Ortiz fight and Wilder will next fight his mandatory fight against Bermane Stiverne."