Folder "Folder_name" isn't making progress

I have the same problem syncing folder from android to PC

on the PC side is says “Folder “xxx” isn’t making progress - check logs for possible root cause. Pausing puller for 1m0s.”…

When I click on the link of “unsynced files” in the web GUI for that folder… it shows buch of files, one .csv, one .db and many .jpeg files… what should I do?