Fix Amazon SP-API Token problem

I follow all instruction in this docs https://github.com/amzn/selling-partner-api-docs/blob/main/guides/en-US/developer-guide/SellingPartnerApiDeveloperGuide.md

I create every thing until i generate the final token token
but when I use the token to call any action I got this message
{
"errors": [
{
"message": "Access to requested resource is denied.",
"code": "Unauthorized",
"details": ""
}
]
}

I need some one help me to solve this problem