First I installed Libreoffice-backports and then tried installing ranger. It didn't work. There was a dependency issue.
Next, I uninstalled Libreoffice-backport and installed ranger without any problem. Normal Libreoffice was still installed.
Then, I installed Libreoffice-backport and It worked.
The problem is solved.
Libreoffice-backports and ranger has conflicting packages [Solved]
Re: Libreoffice-backports and ranger has conflicting packages [Solved]
Installing ranger before installing Libreoffice-backport solves the problem.