Deployment Fails with “TypeError: Failed to fetch” Due to CORS Policy #738
Description
When attempting to publish my Preswald app, the deployment fails with the following error:
Deployment failed: TypeError: Failed to fetch
Upon inspecting the browser’s developer console, I observed the following CORS-related error:
Access to fetch at 'https://deployer.preswald.com/deploy' from origin 'https://preswald.com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Steps to Reproduce:
1. Open the Preswald web editor.
2. Load a CSV dataset and configure the app (e.g., hello.py, preswald.toml).
3. Click on the “Publish” button.
4. Observe the deployment failure and the CORS error in the browser console.
Expected Behavior:
The app should deploy successfully without encountering CORS-related errors. 
Environment:
• OS: [e.g., Windows 10, macOS 12.5]
• Browser: [e.g., Chrome 114.0.5735.199]
• Preswald Version: [e.g., 0.1.0]
Additional Context:
• The issue seems to be related to a misconfiguration of CORS headers on the deployment server.
• Similar issues have been reported by other users, indicating a potential server-side problem.
References:
• GitHub Issue #623
• GitHub Issue #636