Fix: TypeError: Failed to fetch (JavaScript, Browser)
Fix 'TypeError: Failed to fetch' by telling apart CORS, mixed content, an ad blocker, and being offline using the browser's Network tab, not the JS error alone.
Tag: cors
6 articles
RSSFix: AWS S3 CORS Error — Access to Fetch Blocked by CORS Policy
How to fix AWS S3 CORS errors — S3 bucket CORS configuration, pre-signed URL CORS, CloudFront CORS headers, OPTIONS preflight requests, and presigned POST uploads.
Fix: CORS Not Working in Express (Access-Control-Allow-Origin Missing)
How to fix CORS errors in Express.js — cors middleware not applying, preflight OPTIONS requests failing, credentials not allowed, and specific origin whitelisting issues.
Fix: CORS Error with Credentials – Access-Control-Allow-Credentials and Wildcard Origin
How to fix CORS errors when using cookies or Authorization headers, including 'Access-Control-Allow-Credentials' and wildcard origin conflicts.
Fix: CORS preflight request blocked — Response to preflight does not have HTTP ok status
How to fix 'Response to preflight request doesn't pass access control check' and 'preflight channel did not succeed' CORS errors by handling OPTIONS requests, setting correct headers, and configuring your server.
Fix: Access to fetch has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header
How to fix 'Access to fetch at ... from origin ... has been blocked by CORS policy: No Access-Control-Allow-Origin header is present on the requested resource' in JavaScript. Covers Express, Django, Flask, Spring Boot, ASP.NET, nginx, Apache, dev proxies, preflight requests, credentials, and edge cases.