How to resolve ‘preflight is invalid (redirect)’ or ‘redirect is not allowed for a preflight request’
Short answer: Make the request URL in your code isn’t missing a trailing slash. A missing-trailing-slash problem is the most-common cause of the error cited in the question. But that’s not the only cause — just the most common. Read on for more details. When you see this error, it means your code is triggering your browser … Read more