According to E! Online, she scrapped a gig that was to be held on May 3 in Oakland, California.
She is also said to have scrapped scheduled stops in Phoenix, Arizona, Biloxi in Mississippi and two concerts in Texas.
Jennifer last staged a gig on May 2 in Los Angeles, and turned it into a birthday tribute to the manager who helped her cope after the 2008 murders of her mother, brother and nephew.
She surprised her manager with a cake and a chorus of Happy Birthday, reports Contactmusic.
The audience of the Nokia Live also saw star guests — like Chaka Khan and Earth, Wind and Fire stars Philip Bailey and Verdine White — joining Jennifer on stage.
It is said that the scrapped Oakland gig will now be staged on May 19.
Other postponed dates are expected to be rescheduled shortly. (ANI)