Our application uses OAuth to get user’s access token. We noticed that after a while tokes are revoked and API calls fails with unauthorized errors. An example:
```json
{
"type": "error.list",
"request_id": "0003hg8qe7evlq01dqcg",
"errors": [{ "code": "unauthorized", "message": "Access Token Invalid" }]
}
```
May I ask if access tokens obtained through OAuth have expiration date? If there a way to debug why token is invalid now?
