Can’t generate token for Adobe Lightroom Creative Cloud

Hey Everyone!
From a long time I’m trying to generate an API for my Lightroom Creative Cloud. But still couldn’t reach the point. I’ve followed the documentation part ( & created integration, created project of lightroom services.
And while reaching the 4th point that is checking the Service Health Check the error I got was while (1) {}{“code”:“403000”, “description”:“Api Key is required”}.
Then I moved to POSTMAN for that I had to generate an access token to develop an API. But when redirecting to the site doesn’t show any POP-UP or access token not even showing me any error. Through this site I’m generating token: OAuth 2.0 Playground
I’ve my CLIENT ID & SECRET also provided my URI in the project for generating token but can’t generate it.
Eagerly seeking the community attention please.

Kind Regards,