Invalid OAuth token error

Fortunately, I sent the request from the beginning and received the token in the form of JSON. By the way, how can I use the API using the token I received now?
The status of 401 is the result of the api requested by axios.get().

Below is the response I received after running step 3.

{
    "access_token": "access_token",
    "expires_in": 14376,
    "refresh_token": "refresh_token",
    "scope": [
        "viewing_activity_read"
    ],
    "token_type": "bearer"
}