Some thumbnails are missing and View button is not available on iPad

Hi. I have just installed Plex Server on my PC (Windows 10, i5-2500K, HDD 2 TB (raid 1), 8GB RAM. I created only one Library referencing to my pictures (about 1800 pieces). After the while seems that scanner processed the folder completely , CPU and disk utilization for Plex processes is 0%. The result is:

  • only about 50% of thumbnails is visible the rest is empty plex rectangles (I have the same view via web browser on PC and on iPad)

  • on iPad “View” button (grid like icon) is not available (greyed), only default view is available, which is a bit ridiculous for great multimedia server on the most appropriate device to watch photos

  • “recently added” section has empty thumbnails (no names, no pictures)

Is that all that I can expect from this system? I planned to invest in new NAS and go for premium version of Plex, but after this short evaluation I could not be disappointed more. I will appreciate if I get support.