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, project of lightroom services.
And while reaching the 4th point that is checking the Service Health Check the error I got with this URL( was while (1) {}{“code”:“403000”, “description”:“Api Key is required”}.
Then I moved to POSTMAN for that I was generating an access token to develop an API. But redirecting to the site doesn’t show any POP-UP or access token not even showing me any error.
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,