AngularJS "Error: [ngRepeat:dupes] Duplicates in a repeater are not allowed. Use 'track by' expression to specify unique keys "

I have the following array in my scope:

array (2) { [0]=> object (stdClass) # 2 (6) { [“nombre”]=> string (2) "we" [“ID”]=> string (1) "1" [“necesario”]=> string (2) "12" [“fecha”]=> string (2) "12" [“zona”]=> string (2) "12" [“genero”]=> string (0) ""} [1]=> object (stdClass) # 4 (6) { [“nombre”]=> string (2) "we" [“ID”]=> string (1) "4" [“necesario”]=> string (2) "12" [“fecha”]=> string (2) "12" [“zona”]=> string (2) "12" [“genero”]=> string (2) "23"}} [{“nombre”:”we”,”ID”:”1″,”necesario”:”12″,”fecha”:”12″,”zona”:”12″,”genero”:””},{“nombre”:”we”,”ID”:”4″,”necesario”:”12″,”fecha”:”12″,”zona”:”12″,”genero”:”23″}]'

And I want to create a row in a table for each element of it, I've tried with

ng-repeat = "request in requests"

but it gives me the error of the title of the message. When adding

ng-repeat = "request in requests track by solicitud.ID"

I keep giving the same error, and if I add it

ng-repeat = "request in track by $ index requests"

the browser is blocked and stays in a kind of infinite loop. Can somebody help me? Thank you