Problem with the integration of my Nextcloud client

Hello
I have a problem with the integration of my Nextcloud client in Windows.
Everything worked perfectly until yesterday. I can no longer share via the context menu (right click on the file, share nextcloud ") and I no longer the small icon that indicates the synchronization of the files.

Would you have an idea?
Sorry for my English.

As far as I know, changes to the context menu are made in the registry. Your nextcloud client should only be able to edit the registry during installation/deinstallation.

Is it possible that you run some clean up tool in additon?

Here is a manual how to edit the registry (manual or with special software):