Mounting remote SMB files

I have exported a folder from my Mac using SMB and want to mount it on a Virtualbox VM running NixOS. I found a nice description of how to do this on the NixOS wiki at https://nixos.wiki/wiki/Samba

However, when I try to “ls” the directory I get the message “cannot open directory: no such device”

When I run Dolphin and try to view it I get the slightly more informative message “mount /mnt/metabooks: operations permitted for root only”. So I tried “ls” as root, but that didn’t work. Apparently some program needs to be suid root, or maybe a configuration file needs to be changed to let non-root programs mount directories. I have never tried to mount a SMB folder before, so can only imagine what could go wrong. Does anybody have suggestions for me to try?

Did you find a solution?