Payment subdomain is responding.
This root page confirms the payment gateway is up. Use the API endpoints below from your main site or merchant integration.
Create Payment
https://payment.mypaymentbd.com/api/payment/create
Verify Payment
https://payment.mypaymentbd.com/api/payment/verify
If API requests work but browser assets still fail, the remaining issue is server configuration or document root mapping, not the application route.