all my Windows computers have stopped Sync

Since I upgraded my icloud storage a month ago all my windows computers and Iphone's have stopped sync.

each computer is saying sync pending for the last month.

I can login to my icloud account on line and upload each fine individual the down load it onto another computer but it has just stopped doing it automatically.

how do I fix this?

If I logout it says all my files will be deleted that haven't been uploaded that haven't been sync