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Errors: CORSMultipleAllowOriginNotAllowed

Reason

Reason: Multiple CORS header ‘Access-Control-Allow-Origin’ not allowed

What went wrong?

More than one Access-Control-Allow-Origin header was sent by the server. This isn't allowed.

If you have access to the server you can change your implementation to echo back an origin in the Access-Control-Allow-Origin header. You cannot send back a list of origins, because browsers only accept a value that is either a single origin or null

See also

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS/Errors/CORSMultipleAllowOriginNotAllowed