Can't save changes, erase, etc.

Any time I want to move a file to the trash or save some change or more things I don’t remember, it appears an advise telling that this can’t be done. I have all the permits, also tried to start Digikam as root but I have no results. I didn’t find anything in the manual. I am running 7.1.0 version in Xubuntu 20.04.
Could anyone help me?