Failed to fetch error – ReactJS + GraphQL [closed]

We get "Failed to fetch" error when ReacjJS connecting to GraphQL. The error doesn’t give any more details as it seems it is failing to connect GraphQL server. We tried to fix CROS, added IP address instead of local host or domain.. nothing seem to be working. Need help.

Worked on CORS

Changed IP address to 0.0.0.0 instead of local host or domain name in API URL

Tested in multiple environments (dev, qa, UAT, prod)