Fedora 28 is missing a required library, libnsl.so.1. Without it you will get "cannot verify the license" errors if already installed, and otherwise Office 2010 will fail to install.
To fix:
sudo dnf install libnsl.i686 libnsl.x86_64
Unfortunately, running /opt/cxoffice/bin/cxdiag will not tell you that this library is missing. I hope CodeWeavers can fix this.
By the way, to install all required libraries for CrossOver:
sudo dnf install mesa-libGLU.i686 isdn4k-utils.i686 libgphoto2.i686 mpg123-libs.i686 openal-soft.i686 ocl-icd.i686 mesa-libOSMesa.i686 sane-backends-devel.i686 libxslt.i686 libnsl.i686 libnsl.x86_64