Facebook Conversion APi-Purchase Event for shopify

Hello guys. I need help with setting up conversion API for purchase events in Shopify. I have added the following code in the checkout page:

           {% if first_time_accessed %}                                          
                                window.dataLayer = window.dataLayer || [];                                            
                                var shipping_price = '{{shipping_price | money_without_currency }}';
                                shipping_price  = shipping_price.replace(",", ".");
                                var total_price = '{{total_price | money_without_currency }}';
                                total_price  = total_price.replace(",", ".");
                                var tax_price = '{{tax_price | money_without_currency }}';
                                tax_price  = tax_price.replace(",", ".");
                                    'page_type': 'purchase',
                                    'event': 'purchase',
                                    'currency': "{{ shop.currency }}",
                                    'totalValue': total_price,
                                    'shipping': shipping_price,
                                    'tax': tax_price,
                                    'payment_type': '{{order.transactions[0].gateway}}',
                                    'transaction_id': "{{order.name}}",
                                {% endif %}

And i created the data layer also but when i check the purchase event then it is not triggering. Below is the recording of my google tag manager you can easily check it.

Recording video


You are using the event name “gtm.js” in the trigger, instead of “purchase”.