eBay API Access Token Issue: The requested scope is invalid, unknown, malformed, or exceeds the scope granted to the client

I'm working with the eBay API and encountering an issue during the OAuth process. I'm trying to receive an access_token through this URL https://api.sandbox.ebay.com/identity/v1/oauth2/token

I'm making a POST with this data (please, also, see the Postman screenshot below):

- Headers: 
  - Content-Type: `application/x-www-form-urlencoded`
  - Authorization: <Base64 encoded client ID and secret>
- Body (x-www-form-urlencoded):
  - grant_type: client_credentials
  - scope: https%3A%2F%2Fapi.ebay.com%2Foauth%2Fapi_scope https:%3A%2F%2api.ebay.com%2oauth%2api_scope%2sell.account
  - redirect_uri: <My redirect URL>

After making the POST request, I get the following response:

{
    "error": "invalid_scope",
    "error_description": "The requested scope is invalid, unknown, malformed, or exceeds the scope granted to the client"
}

You mixed a scope "Authorization Code Grant Type" and " Client Credential Grant Type" even if you assigned "grant_type" is "client_credentials"

Authorization Code Grant Type

https://api.ebay.com/oauth/api_scope/sell.account

Client Credential Grant Type

https://api.ebay.com/oauth/api_scope

So have to use same "Client Credential Grant Type" scopes

I demo two same category scopes from "Client Credential Grant Type"

https://api.ebay.com/oauth/api_scope https://api.ebay.com/oauth/api_scope/buy.guest.order

Username and Password copy from your Application Keys (client id and client secret) - the following image.

You can get the scope list from here

https://developer.ebay.com/my/keys

Client Credential Grant Type

Authorization Code Grant Type