Facebook recently announced they're no longer supporting Groups through their API, meaning Cloud Campaign and other 3rd parties won't be supporting Groups. To help maintain the audience you've built in your groups, you can create a page, or link an existing one, to your Group.
These steps from Meta will help you move your audience over to your Page.
If you have any further questions, please feel free to reach out to our support chat, customersupport@cloudcampaign.com, or your Customer Success Manger!