Title: Fix React Booking System Submission Error (Hetzner API Backend)

Title: Fix React Booking System Submission Error (Hetzner API Backend) We have a custom online scheduling system used on multiple medical websites. The scheduling system is a React-based widget with an API backend hosted on Hetzner. The booking process loads correctly and users can: • Select a service • Select a date and time • Enter patient information However, when the user clicks "Schedule Appointment", the booking fails and displays the following message: "We're sorry. Something went wrong, try again later." The issue appears to occur during the final submission step. Current Situation • Front-end loads normally • Appointment slots display correctly • User information can be entered • The scheduling system successfully reaches the patient information screen and accepts user input • Error occurs only after clicking "Schedule Appointment" • Website itself is functioning normally • Scheduling system has worked previously • No intentional changes were made before the issue appeared • Backend is hosted on Hetzner • React-based scheduling widget • Custom API integration Video Demonstration of the Issue A short Loom video demonstrating the problem is available here: loom.com/share/bb362a5da4e54fca9ef027fe84628f94?focus_title=1&muted=1&from_recorder=1 The video shows the complete workflow from appointment selection through patient information entry and the resulting error message after submission. What We Need We are NOT looking for a redesign or rebuild. We need a developer who can: 1. Diagnose the root cause of the booking failure. 2. Determine whether the issue is related to: • Front-end validation • API request failure • Backend error • Database issue • CORS issue • Authentication/session issue • Hosting/server configuration issue 3. Fix the issue. 4. Verify successful appointment creation. 5. Provide a brief explanation of what caused the problem. Access Available We can provide: • Website access • Browser console screenshots • FTP/SFTP access • Server access if needed • Relevant code access Deliverables • Root cause identified • Booking system successfully submitting appointments • Confirmation that appointments are being stored correctly • Summary of changes made This is a troubleshooting and repair project, not a rebuild.