simple_oauth refresh token works only one time

I use the [simple_oauth][1] module to authenticate the user.

I have generated the first access_token using the grant_type=password.

then I have tried to get a new access_token using my refresh_token received from first request :

POST /oauth/token

grant_type:refresh_token
refresh_token:def50200d3c74fa2e41a886a6ff1...
client_secret:l0r3m1psum

the first time I execute the request it returns the new access_token :

{
    "token_type": "Bearer",
    "expires_in": 300,
    "access_token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJS..",
    "refresh_token": "def502002b9ce17870bc285427a6.."
}

the problem is the second time I run the same request it Doesn't works and I get 401 unauthorized with this HTML body :

{
    "error": "invalid_request",
    "error_description": "The refresh token is invalid.",
    "hint": "Token has been revoked",
    "message": "The refresh token is invalid."
}

for the second request I have used the same refresh_token(I'am sure it not expired I have set ttl to 78000 for test) :

POST /oauth/token

grant_type:refresh_token
refresh_token:def50200d3c74fa2e41a886a6ff1...
client_secret:l0r3m1psum

grant_type:refresh_token request will enable us to get new access_token as long as refresh token not expired?

but it is like getting expires after just executing a request one time , if I generate a new refresh_token using the grant_type:password in my case the grant_type:refresh_token request works fine .

but in [1]: https://www.drupal.org/project/simple_oauth

This is working as expected. You receive a new access token and refresh token. You must use those in subsequent requests.