Hello   @Ad505 

From photo the thumbnails failed to load, that could be due to the poor or lagged network.

You could check if that can be fixed by quitting or force closing the APP and reopen the app. 

Try to switch between Wi-Fi network or mobile data on the phone.

Please also check if there is APP update is available in the APP store, there should be a newer APP now. 

If still the same, when the problem occurs, please connect the phone to the home Wi-Fi network and see if the thumbnail will load. 

What is the model of your phone and its OS version. 

Please try to install the debug APP I shared with you via PM and help collect the APP log when problem occurs and attach the log here , thank you.