HTML Dynamic input fields form validation in Codeigniter

Question

I have created this HTML form for adding education details dynamically. I tried to add form validation on it in Codeigniter but form validation is not running.

<div class="row p-0">
    <div class="col">
        <div class="form-outline">
            <input
                type="text"
                name="Clg_name[]"
                placeholder="College Name"
                class="form-control clgName"
            />
        </div>
    </div>

    <div class="col">
        <div class="form-outline">
            <input
                type="text"
                name="unv_name[]"
                placeholder="Univer. Name"
                class="form-control unvName"
            />
        </div>
    </div>

    <div class="col">
        <div class="form-outline">
            <input
                type="text"
                name="Cname[]"
                placeholder="Course Name"
                class="form-control Cname"
            />
        </div>
    </div>
</div>

<!-- Degree type input -->
<div class="form-outline mt-3">
    <div class="row">
        <div class="col">
            <div class="form-outline">
                <label>Grade</label>
                <input
                    type="text"
                    name="grade[]"
                    placeholder="Grade"
                    class="form-control grade"
                />
            </div>
        </div>
        <div class="col">
            <div class="form-outline">
                <label>Start Date</label>
                <input type="date" name="s_date[]" class="form-control startDate" />
            </div>
        </div>

        <div class="col">
            <div class="form-outline">
                <label>Last Date</label>
                <input type="date" name="e_date[]" class="form-control endDate" />
            </div>
        </div>

        <div class="col">
            <label class="form-label">Degree Type</label>
            <select name="Cmode[]" class="Cmode">
                <option value="">--Select--</option>
                <option value="ug">Under Graduation</option>
                <option value="pg">Post Graduation</option>
                <option value="mphil">M. Phill</option>
                <option value="phd">PHD</option>
                <option value="diploma">diploma</option>
            </select>
        </div>

This is my codeigniter form validation code.

public function get_education(){

      $validation = array(
         array(
            "field"=>"Clg_name[]", 
            "label"=>"College name", 
            "rules"=>"required|alpha"
         ),
         array(
            "field"=>"unv_name[]", 
            "label"=>"University name", 
            "rules"=>"required|alpha"
         ),
         array(
            "field"=>"Cname[]", 
            "label"=>"Course name", 
            "rules"=>"required"
         ),
         array(
            "field"=>"grade[]",
            "label"=>"Grade", 
            "rules"=>"required|numeric|decimal"
         ),
         array(
            "field"=>"s_date[]", 
            "label"=>"Starting date", 
            "rules"=>"required"
         ),
         array(
            "field"=>"e_date[]", 
            "label"=>"Ending date", 
            "rules"=>"required"
         ),
         array(
            "field"=>"Cmode[]", 
            "label"=>"Course Mode", 
            "rules"=>"required"
         )      
         
      );

      $this->form_validation->set_rules($validation);
      

      if($this->form_validation->run($validation)){
         
         

         $this->load->model('insertData');
         $IDs = $this->insertData->fetchIDs();
         
         $result = $this->insertData->educationDetails($education, $IDs);
         echo $result;
         $upload_msg1 = 'Successfully saved.';
         $this->load->view('User/Resume/educational_details', ["upload_msg"=>$upload_msg1]);
      }else{
         echo "validation is not run";
         $this->load->view('User/Resume/educational_details');
      }

   }

I have sent form data by ajax. Form data accessed in controller but my form validation is not running.

$this->form_validation->run($validation); is returned "bool(false)";

Please any suggestions.