Anyone that can tell me how to use cors properly? 😕 My windows computer can't send graphql requests to my mac, but I can visit the graphql endpoint and use playground.

CORS is normally off by default. What you're likely seeing is a server error propagating up without CORS (e.g. a 500 error without a CORS header)

I keep getting 400 error

Then you'll want to deal with that error. It's not the CORS problem

https://github.com/apollographql/apollo-client/issues/1233 seems to me that its CORS

Ok, then good luck with that path