Women’s tennis star Maria Sharapova was banned from tennis for two years on Wednesday for testing positive for a banned substance.

At the Australian Open in January Sharapova tested positive for meldonium, which is also known as mildronate. The World Anti-Doping Agency had banned athletes from using meldonium on January 1 and Sharapova said that she was unaware that it was a banned substance. She had been taken meldonium because of irregular electrocardiogram results as well as her family having a history of heart issues and diabetes.

An independent three-person panel appointed by the International Tennis Federation, which made the ruling, said that Sharapova didn’t intend to cheat and that she took sole responsibility and fault for the positive test, according to the Associated Press.

Sharapova announced that she had failed a doping test at the Australian Open in March and was provisionally suspended. She said in a post on Facebook that she will appeal the ban.

"Today, with their decision of a two-year suspension, the ITF tribunal unanimously concluded that what I did was not intentional," Sharapova said in a statement on Facebook, "The tribunal found that I did not seek treatment from my doctor for the purpose of obtaining a performance enhancing substance. The ITF spent tremendous amount of time and resources trying to prove I intentionally violated the anti-doping rules and the tribunal concluded I did not. You need to know that the ITF asked the tribunal to suspend me for four years -- the required suspension for an intentional violation -- and the tribunal rejected the ITF's position."

Sharapova is a five-time Grand Slam champion. She won the Wimbledon championship in 2004, the U.S. Open championship at age 19 and the Australian Open championship at age 20. At age 18, she became the top-ranked player in women’s tennis. Her last big win came at the French Open in 2014 and she hasn’t played since the quarterfinals of the Australian Open and is ranked 26th this week, according to ESPN.

Sharapova’s ban is scheduled to end January 25, 2018 since its backdated to the Australian Open.