How to fix iOS 12 Safari Cors preflight error?

Question

I am trying to understand CORs a little better as several users of our web app are complaining since they upgraded to iOS 12 they are receiving preflight errors.

The

Answer 1

If it says Header not allowed in "Access-Control-Allow-Headers", You can fix it by adding the specific Header from the server side, where you send "Access-Control-Allow-Headers". because wildcard is not working i.e “Access-Control-Allow-Headers”: “*"

It should be “Access-Control-Allow-Headers”: “*, Accept, Content-Type, Content-Length, Accept-Encoding, CUSTOM-ALLOWED-HEADER”