NetworkError: 500 Internal Server Error

I have a code that forms the user's profile screen. On the side of the name it has the edit option, which when clicked opens an inline edit ( form-x-editable.html ). Even in that part it is working normally, but clicking to save it gives the error NetworkError: 500 Internal Server Error . I do not know what could be wrong. My code is in MVC

View:

<span rel="tooltip" data-placement="right" data-original-title="Nome">
                            <a href="form-x-editable.html#" style="font-size: 14px;" id="nome" data-type="text" data-placement="top" data-pk="14" data-original-title="Nome">Editar</a>
                        </span>

Javascript:

var nome;
nome = '<?= $dados->nome ?>';
$('#nome').editable({
            url: '/Controller/editar',
            type: 'text',
            pk: 14,
            name: 'nome',
            title: 'Nome',
            params: function (comp) {
                comp.id_span = 'span14';
                comp.id = di_id;
                comp.e_id = epr_id;
                return comp;
            },
            ajaxOptions: {
                type: 'GET',
                dataType: 'json',
                contentType: 'application/json'
            },
            success: function (j) {
                $('#span14').html(j.nome);
                $('#dispName').empty();
                $('#dispName').html(j.nome);
            },
            value: nome,
            display: false
        });

Controller:

public function editar(){
        switch($this->input->get('id_span')){
            case 'span14':
                $data['nome'] = $this->input->get('value');
                $id = $this->input->get('id');
                $e_id = $this->input->get('e_id');
                $this->session->set_userdata('nome',$this->input->get('value'));
                $this->MT->editPerfil($id,$e_id,$data);
                break;
        }
        echo json_encode($data);
    }
}

Model:

public function editPerfil($id, $e_id, $data) {
        if ($this->vrfUsrEmp($e_id)) {
            if (isset($data['nome'])) {
                $this->db->set('nome', $data['nome']);
            }
            $this->db->where('id', $id);
            $this->db->where('e_id', $e_id);
            $this->db->update('NomeTabela');
            return $this->db->affected_rows();
        } else {
            return false;
        }
    }