|Oprah Winfrey and Rosie O'Donnell (Photo: PerezHilton)
The problems are believed to have started when Oprah first called the comedienne to deliver the news.
A source said: "It was a very strained conversation, obviously. Oprah wanted to handle the announcement of the cancellation in a professional and dignified manner. Rosie thanked Oprah for the opportunity and ended the conversation very abruptly."
Rosie, 49 - who is engaged to headhunter Michelle Rounds - is said to have ignored her friend's subsequent pleas to call her so they could work on the press release together.
The insider told RadarOnline.com: "Rosie didn't like the initial language of the press release because she felt that it placed sole responsibility of the failure of the show on her. Oprah didn't need to get Rosie's input or approval for the press release, but she was trying to be gracious.
"[OWN] got a phone call from Rosie's camp, explaining what needed to be included into the press release. This is Oprah's network, and she has the final say. Oprah told her staff to have Rosie call her directly to address her concerns. Rosie never called Oprah. She was having her people do all the dirty work for her."