I'll need some specific information to help you figure this out.
What version of Android & Lightroom are you working on? Please record your screen when you try this & upload to Creative Cloud files (https://assets.adobe.com/files) and share it with us.
Log on to Lightroom Web (https://lightroom.adobe.com) & check for all the images that have synced & uploaded to the cloud. Once you're sure everything is backed up to the cloud, try reinstalling Lightroom & let me know how it goes.