Error validating current user and server
The validate App Id function in assumes a passing of the literal access_token (String) but what's actually passed is an auth Data structure within which lives a key called "access_token"..
so should actually be trying to append access_token.access_token to the graph request, and not just access_token.
To get this information you can use our debug tool, or you can use the API endpoint.
To use the API, you can issue a Graph API request: time passed to your App along with the access token, your app may only learn that a given token has become invalid is when you attempt to make a request to the API.
Anytime you get this error, you should run the user back through the auth flow.You can expect that they will grow and shrink over time.Please use a variable length data type without a specific maximum size to store access tokens.Also, in response to certain events that are security-related, access tokens may be invalidated before the expected expiration time.In most apps, the best way to handle expired tokens is to capture the error messages thrown by the API.