Sorry to hear about the trouble. This generally happens because of sync issues, so could you please share a few more details like:
1. what version of Adobe XD are you using? 2. Are other collaborators on the latest version of XD? 3. Have you checked if there are any updates available for Creative Cloud app? Please close CoreSync and other Adobe services from the Task Manager/Activity Monitor and then reboot your computer. Once rebooted, please check if it still shows as disconnected. We'll also need a screenshot of the About XD info page.