Synchronisation failed due to open file which are in fact not open

I was working on one station in Indesign saved in to Creative cloud. A little later my system crashed (due to other progamm). When I switched over to another station Creative Cloud came with a message that synchronisation failed as files in a folder are still open. 
So I went back to other station opened and closed InDesingn file. Back again the second station Creative Cloud still will not sync files.

How to solve this issue?

Regards, Marcel