Hello there,
I believe the username and user password in your request payload doesn't match with the client ID and client secret that you are sending (aka consumer key and consumer secret). Please login to the developer platform with your username and user password and verify whether you are sending the correct client ID and client secret in your request payload.
Refer to the Getting Started section in the Knowledge Center to learn how to create/check your client ID and client secret. Alternatively, you may click on this link
https://developer.equinix.com/docs?page=/dev-docs/fabric/getting-started/getting-access-token- Equinix Developer Community