cifs-utils missing

Hi. I'm brand new to Ubuntu. Just installed it on a Mac. I want to access data stored on a Mac airport - not the time machine data, but data stored in a directory on the airport. I got as far as needing to mount it, but my install (20.04.1 LTS) doesn't seem to have the utils. I tried to install cifs-utils but I got this:


sudo apt-get install cifs-utils
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package cifs-utils is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'cifs-utils' has no installation candidate


I've been on Google for an hour or so, but can't fix it. I tried apt-key update but got a message that this command can only be used by root.

Any idea how I can get cifs-utils? If there's an easier way to get at the files on my Mac Airport then that would also be useful.

Thanks,

Lee