Lightroom app thumbnail appears as black boxes (Android)

I have a problem with Adobe Lightroom App! I Am a regular user of the lightroom app. I am not able to see the uploaded images as thumbnails in the Lr home screen, the images appear as black boxes in the Lr home screen after few hours of uploading, and added presets also getting disappeared after few hours. Does any one have the same issue, how to resolve this error?

[Moderator: Moved to the Lightroom mobile forum]