The Keys generated for the API connection are not valid. 

Regenerate the keys in the LinkedIn Developer console, and update the new values under the API section of Administration - SItes & Settings in BBNC.  Be sure you update any other applications that are using the LinkedIn API keys.

To regenerate the keys:
1) Login to your LinkedIn Developer account.
2) Select the edit option for the API used in your BBNC site
3) Select to Revoke the OAuth Keys
4) Select Save at the bottom of the page
5) Select Regenerate Keys
Please note the Token values with remain the same, but the keys will change
 
6) Select Save

The Administration User Guide describes the steps to take to update the LinkedIn API information:
1) Login as a Supervisor level user of BBNC
2) Navigate to Administration - Sites & Settings
3) Select the API tab
4) Under LinkedIn, enter the keys, token, and secret for your LinkedIn application. The LinkedIn Group Join part requires this information to access LinkedIn data. For more information about the LinkedIn Group Join part, see Design LinkedIn Group Join.
To determine this information, view your application on LinkedIn. When you do this, make sure you enter your website domain in the JavaScript API domain list in your application. For more information, visit the LinkedIn Developer Network.
5) 
To save the settings, click Save.