I am using Dropbox to share working files between a couple of computers, on Windows 11 and the other on Kbuntu Linux. Everything worked fine for a while but now, the files I save from the Linux box do not appear to file explorer on the Windows box. The files are available to Linux - I just downloaded one from Dropbox and copies it to a USB drive and brought it to the Windows box where I copied it up to Dropbox. It went into the Dropbox file it just came from as if new. If I go back to linux and try to copy it, it sees a copy already there.
Any suggestion on how to fix this?