Reason: CORS header 'Access-Control-Allow-Origin' missing
What went wrong?
The response to the CORS request is missing the required
Access-Control-Allow-Origin header, which is used to determine whether or not the resource can be accessed by content operating within the current origin.
If the server is under your control, add the origin of the requesting site to the set of domains permitted access by adding it to the
Access-Control-Allow-Origin header's value.
For example, to allow a site at https://amazing.site to access the resource using CORS, the header should be:
You can also configure a site to allow any site to access it by using the
* wildcard. You should only use this for public APIs. Private APIs should never use
*, and should instead have a specific domain or domains set. In addition, the wildcard only works for requests made with the
crossorigin attribute set to
anonymous, and it prevents sending credentials like cookies in requests.
Warning: Using the wildcard to allow all sites to access a private API is a bad idea for what should be obvious reasons.
To allow any site to make CORS requests without using the
* wildcard (for example, to enable credentials), your server must read the value of the request's
Origin header and use that value to set
Access-Control-Allow-Origin, and must also set a
Vary: Origin header to indicate that some headers are being set dynamically depending on the origin.
The exact directive for setting headers depends on your web server. In Apache, add a line such as the following to the server's configuration (within the appropriate
<VirtualHost> section). The configuration is typically found in a
.conf file (
apache.conf are common names for these), or in an
Header set Access-Control-Allow-Origin 'origin-list'
For Nginx, the command to set up this header is:
add_header 'Access-Control-Allow-Origin' 'origin-list'