Dropbox doesn't sync all files

Question

SQL Server

Dropbox won't sync some files for some reason. If you right-click on the icon, you can see the message
Cant sync %filename%. Rejected by server.

The reason for the refusal is not indicated anywhere. The files are small in size, the names of the files are unremarkable. If I delete the file from the synchronization folder and drop it again, I get the server failure again.

What could it be from?

Answer 1

1. Try adding a file via online upload. If everything works, then most likely something with the desktop application.
2. Try to reinstall the dropbox, maybe a virus / antivirus has gnawed it.

Answer 2

And what kind of files, if not a secret. A few examples would be desirable.