API Explorer returns 403 Forbidden

[octaneologists]

Hi, I've just joined the developer program and am trying to make my first call using the API Explorer (sandbox) and no matter what I try, I get a 403 Forbidden:

{
"errors": [
{
"errorId": 1100,
"domain": "ACCESS",
"category": "REQUEST",
"message": "Access denied",
"longMessage": "Insufficient permissions to fulfill the request."
}
]
}

I'm trying to use the Sell API > Inventory API > getInventoryItems.

I have used the 'Get OAuth Application Token' link to successfully fill in the token and have tried refreshing, logging in/out and nothing makes any difference. Any ideas what I'm missing here?

[developer_support@ebay]

Hi @octaneologists ,

You need a user access token that grants your application permission to make API calls on behalf of a specific eBay user.

Inventory API calls like getInventoryItems call require an access token created with the authorization code grant flow, using one or more scopes from the following list:

https://api.ebay.com/oauth/api_scope/sell.inventory.readonly
https://api.ebay.com/oauth/api_scope/sell.inventory

You can also select the "Get OAuth User Token" option in the API Explorer page. 

Getting User access tokens via the Developer Portal: https://developer.ebay.com/api-docs/static/oauth-ui-tokens.html#user