The former couple - who separated in September 2016 - was previously working towards a cordial co-parenting relationship. But tensions have recently escalated between them ahead of next month's custody trial and they've now stopped attending the counselling sessions, a source told Us Weekly magazine.
The Hollywood duo - who have Maddox, 19, Pax, 16, Zahara, 15, Shiloh, 14, and 12-year-old twins Knox and Vivienne together - are currently at loggerheads over how much time they each spend with their children.
However, Maddox is able to make his own decisions about his schedule due to his age.
Speaking about their custody battle, an insider previously explained: "Brad wants 50/50 joint physical and legal custody of the kids. Angelina has been unagreeable to those terms.
"[She] will only agree to talk about an agreement if the home base for the children isn't Los Angeles. The younger kids are in school in Los Angeles, which Angelina has always been opposed to.
"They are very smart and are eager to attend school in person [amid the coronavirus pandemic]."
By contrast, the celebrity duo previously appeared to be moving towards a long-term solution when Brad, 56, was photographed leaving the 45-year-old actress' house in June after spending several hours with the kids.
And in July, a source close to the situation confirmed that they had been making "progress" in their dispute.
The insider explained at the time: "Brad and Angelina have continued to navigate a path forward for their children. There has been progress."