PS cc 2018 welcome screen stopped showing Lightroom photos

Hello,

During my first few days of using PS cc 2018, it displayed preview images of all of my lightroom albums and recently taken photos (welcome screen, LR photos). It worked great. then last night the previews stopped showing. Instead of a preview, just all blank images. If I click on the image, the photo is still there, and will still open. But obviously, a problem because I can't see what I'm opening without a preview.

Couple of things

1. Other previews in the welcome screen work fine ('recent', and 'cc files').
2. My Lightroom classic cc 2018 works fine. If I add a new photo to lightroom classic, it shows up (without a preview image) in the photoshop welcome page LR photos section (see the sync is working)
3. My lightroom cc is working fine. New photos added to lightroom classic show up in lightroom cc.
4. I fixed lightroom classic 'stalled upload' problems by deleting files which had an error - this did not help.
5. I renamed the lrcat file in lightroom classic, but this didn't help.

So - is anyone else having this problem in photoshop cc 2018?

Any ideas?

Thank you.