While working in XD, I use the Live Preview for mobile all the time. Until recently. The live preview locked on one of my design files and wouldn't load the new file. Then when I tossed out the mobile app and redownloaded it and signed in, it now won't recognize when the device is plugged in. I just get the prompt screen. Yet, I can still get the cloud files to load and interact with those. But it's not the same. Any thoughts? Do I need to dump and reload my desktop app?
I use the Creative Cloud Sync version of XD and I'm caught up. And I run it from my MacBook Pro running 10.14.6 (Mojave) and my iPad Pro and iPhone X are all caught up on their updates.
We are sorry to hear you are having trouble doing a live preview in XD. Would you mind sharing the screenshot of your about XD info page? Have you tried connecting a different cable and see if that helps? Please check and confirm if you have the same XD version of both mobile and macbook.