"The Challenge" star CT Tamburello's ex-wife, Lilianet Solares, is dragging him back to court for allegedly failing to follow the court's order in their final divorce judgment ... TMZ has learned.

According to court docs obtained by TMZ, Lilianet claims that CT has not provided health insurance for their son, Christopher Solares.

CT and Lilianet finalized their divorce in November 2023 ... and the reality star was ordered to pay $761 per month in child support, plus $332 for each week that he cannot exercise parenting time due to work.

The exes share joint custody of their kid.

In her new filing, Lilianet said the child support amount was determined based on CT providing health insurance. She said since CT has not done so for three years, she wants the child support recalculated.

CT has yet to respond.