Our checkout flow stalls because the payment page simply never loads. The issue shows up consistently on both desktop and mobile browsers, so it is not a device-specific glitch. I am using a custom payment API—no PayPal, Stripe, or Square—so you will need solid experience reading unfamiliar gateway documentation, tracing requests, and adjusting server-side and front-end code. Here is what I need from you: • Pinpoint the exact reason the payment page fails to render (network calls, authentication, CORS, script errors—whatever is blocking it). • Patch the code or configuration so the page loads fully every time. • Prove the fix by running the full payment flow in at least one desktop browser and one mobile browser and sending me the screen recordings or logs. You will have SSH/FTP access and the gateway docs as soon as we agree to work together. I am ready to test your changes immediately, so a quick turnaround is highly valued.