How to deactivating files_sharing via occ

I have installed owncloud to a ubuntu server 14.04 and I can't login (admin account).. All was working fine, I was able to update the core from the browser some months ago, but now when I am trying to login, I get an error

Access forbidden
CSRF check failed

I searched for this error and I read to

deactivating files_sharing via occ solved the issue

But which is the command?
Thanks a lot!

occ app:disable files_sharing