To capture the values coming along with a visitor the plugin needs to have access to UTM variables (Google’s source, medium, campaign name etc…).
If you are using auto-tagging in your Google adwords account you will need to adjust the URL that the URL for the ad includes the utm variables that you’d like to collect.
For example:
https://YourDomain.com/?utm_source=twitter.com&utm_medium=social&utm_campaign=CampaignName
Alternatively you can choose to change to manual tagging inside your Adwords campaign and configure the tags this way for your ad.