OneDrive does not sync

I have the same OneDrive on 2 pcs, let's call them pc A and B. Until a few weeks ago, if I made a change to a OneDrive folder on pc A, the change would appear on the pc B.

Now the change does not appear in a few seconds, as it used to appear. If I make a change on pc A, I can still view it on pc B, if I restart pc B.

I did some research and one possible cause might be that I have an older version of OneDrive. BTW I use Windows 10 on both pcs.