Opencart 3.0.3.7 Slow at Confirm Checkout page.

Job ID: 35291405

Budget: $10 – $30 USD

Opecart 3.0.3.7 Slow at Confirm Checkout page.
i takes 10 sec to confirm order.

i think it was the extra extension we made modification name "Get Invoice On Order Email"
this option gives me 1 extra invoice to admin email when customer place order

But i disable this function and its stil slow at check out

Need Help solving thisl.
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