How to properly commit and rollback Laravel transaction?

I am using Laravel 5.3, and have function for saving data, but for some reason rollback is not working. What should I change or what is the proper way to make transactions. I am pretty new to this stuff so I am not sure about the right way.

 protected function addKSMembers(Request $request, Application $application, $formName){
    //validation stuff

        if(!$this->testRentType($request->input('type')))
            return false;
         if(!$this->testCompetitionLevel($request->input('level')))
             return false;

     try{
         DB::beginTransaction();
        $sport = Sports::where('id', $request->input('sport'))->first();

        $ksMember= FormKSMembers::firstOrNew([
            'application' => $application->id,
            'unique' => $request->input('unique'),
        ]);

       $status = $ksMember->exists;

       $ksMember->sport_category = $sport->sport;        
       $ksMember->rent_type = $request->input('type');
       $ksMember->sport_type = $sport->sport_type;

       $formResult = $this->getFormResultByString($formName, $application->tender->id, $application->id);

       $this->addCoaches($request->input('coach'), $application->id, $formResult->id, $ksMember->unique);
       $ksMember->save();
       DB::commit();
       } catch(\Exception $e){
       DB::rollback();
}

       if($status)
            $this->extra = "OK";
        return true;        
}

protected function addCoaches(array $coaches, $appID, $formResultID, $resultTableID){
    if(count($coaches) == 0)
        return;
    foreach($coaches as $coach){
        Coaches::create([
            'coach' => $coach['ime'],
            'application' => $appID,
            'form_result' => $formResultID,
            'resultTable' => $resultTableID,
            'education' => $coach['education'],
        ]);
    }
    return;
}

via Tim