This error is from trying to fetch the organization name for your LinkedIn company.
Can you please verify that
1. You have authenticated with LinkedIn before creating the channel
2. Your LinkedIn application is authorized for the Marketing Developer Program
If so, in /plugins/jfbconnect/provider_linkedin/provider/linkedin/channel/company.php at line 52 could you try replacing
$nameUrl = 'https://api.linkedin.com/v2/organizations/'.$orgId.'?projection=(name)';
with
$nameUrl = "https://api.linkedin.com/rest/organizations/" . $orgId;
to see if that has any effect?
-Melissa