I tried the /auth/oauth2/v1/token in API playground, but the request is always not successful. See image below:
The client_id I used is generated from APP KEY(Eikon App Key Generator). Please help.
I would recommend you follow the simple Quick Start tutorial to test your user credentials. I too was unable to fetch a token using the Playground interface and I know my credentials work. Perhaps I'm missing a step or the service may not be working. I will follow up and post an update here.