Solved Problem: Linkedin debug : LinkedIn.com answered "401 : [unauthorized]. The token used in the OAuth request is not valid.

When I was working to accessing group data, i got 401 : [unauthorized] worning.

Don't worry. i solved this by setting variable.

This would look like

// Fetch the required variables.
  $oauth_token = variable_get('linkedin_oauth_token_key', linkedin_group_posts_get_values('token_key'));
  $oauth_secret = variable_get('linkedin_oauth_secret_key', linkedin_group_posts_get_values('token_secret'));
  $group_id = variable_get('linkedin_group_id', '');
  $count = variable_get('linkedin_posts_count', '5'); 

instead of

  // Fetch the required variables.
  $oauth_token = variable_get('linkedin_oauth_token_key', '');
  $oauth_secret = variable_get('linkedin_oauth_secret_key', '');
  $group_id = variable_get('linkedin_group_id', '');
  $count = variable_get('linkedin_posts_count', '5');