URL has been blocked by CORS policy, using Netlify Functions

[hrishikesh]

You skipped over the relevant part and went to background functions. The relevant part was this:

@hrishikesh

Instead, you’d have to set the correct headers from within the Function or the Edge Function. Depending on your setup, the correct way to do this would differ. Some frameworks would offer a built-in way to set custom headers on responses. If you’re writing Functions or Edge Functions yourself, you’d have to include the correct headers accordingly in your code.

In your code, you’ve done that for a 200, but browsers send a preflight request with the OPTIONS method. Since in your code, you’re filtering for the POST method, the response you’re sending for POST doesn’t include those headers causing an issue.

You simply need to add those headers for the HTTP 405 as well.