Photo: Sophy Holland/Bravo (2)

Ramona Singer, Eboni K. Williams

Bravo launched an internal investigation after complaints of racism were filed among the season 13 cast ofThe Real Housewives of New York City, a source tells PEOPLE.

“There was a complaint made betweenEboni K. WilliamsandRamona Singer,” says the source. “Cast and members of the production were interviewed, but the investigation was closed after nothing substantial was found.”

The source says the investigation was one of the reasons the reunion waspushed backandlater canceled.

TMZwas first to report the news of the investigation. Reps for Williams, 38, and Singer, 64, did not immediately respond to PEOPLE’s request for comment. PEOPLE is out to Bravo for comment.

Williams joinedRHONYfor season 13, making her the show’sfirst Black Housewife.

The Real Housewives of New York CitySeason 13 cast.Sophy Holland/Bravo

The Real Housewives of New York City - Season 13 Sonja Morgan, Leah McSweeney, Ramona Singer, Eboni K. Williams, Luann de Lesseps

In an interview withVarietypublished in August, Williams said certain episodes were “really difficult” to relive as they aired, noting her conflicts with Singer andLuann de Lessepsin particular.

Inone June episode, de Lesseps, 56, called Williams “angry,” later leading Williams to sit down with her and explain “why it’s unacceptable to call a Black woman angry in that context today.”

“I was proud of a lot of that conversation,” Williams toldVariety. “I was proud of the listening that all the women did, I was proud of myself.”

She also commended Bravo’s decision to cast her.

“I think the fact that they intentionally went out and found somebody who does this work for a living, who’s a trained litigator, who has a bachelor’s degree in Black Studies, who hosts and produces a show called ‘REVOLT BLACK NEWS’ tells us a bit about their intention,” Williams said. “I have to applaud that. Has it been easy? No. Has it been challenging? Yes. Do I think it wasworth it? Absolutely.”

source: people.com