The club spent more than 200 million euros (RM 933.04 million) on new players in the summer and have a high-interest loan of 300 million euros (RM 1,399.56 million) from United States hedge fund Elliott Management.
Commisso is owner of the New York Cosmos and a driving force behind the NASL last season but which has now suspended play after losing its official division 2 status in the US.
Ronan Evain, chief executive of Football Supporter Europe (FSE), praised the decision.
However, the Italian club had argued that the takeover by Li Yonghong meant they were now stable and released a statement announcing their intention to appeal the decision to the Court of Arbitration for Sport in Lausanne, Switzerland.
Commisso is reportedly backed in the acquisition by Goldman Sachs.
AC Milan are one of European football's most decorated sides having won seven European Cups, but have not competed in the Champions League since 2014.
The San Siro club went on a spending spree amid questions of financial stability of the Rossoneri Sports Investment Lux.
Since 2000, the sale of alcohol, particularly beer, was banned inside the stadiums and venues of UEFA.
Milan had qualified for the Europa League for 2018-19, so what happens with their spot remains to be seen but perhaps Fiorentina will be handed their spot as they finished one place out of the Europa League spots in Italy's top-flight.
The club are reported to have argued their finances are now stable as a result of their takeover by Li Yonghong previous year but UEFA has still acted. The club requested this wavier, but their petition was rejected.
UEFA has said a thorough evaluation was made on the matter.