Get long live access token from Facebook

Solution 1:

There is a way to extend this to 60 days. described here: https://developers.facebook.com/docs/roadmap/completed-changes/offline-access-removal/ under Scenario 4: Client-side OAuth and Extending Access_Token Expiration Time through New Endpoint

Edit: In order to extend the access token you need to make the following request with your short lived access token:

https://graph.facebook.com/oauth/access_token?             
    client_id=APP_ID&
    client_secret=APP_SECRET&
    grant_type=fb_exchange_token&
    fb_exchange_token=EXISTING_ACCESS_TOKEN 

Solution 2:

Due to a bug in Facebook, some users will have to unauthorize the app before Facebook will issue the long-lived tokens.