setcap 'cap_net_bind_service=+ep' does not work

If I install endlessh through apt install endlessh then the command setcap 'cap_net_bind_service=+ep' /usr/local/bin/endlessh does not work and I get

Failed to set capabilities on file /usr/local/bin/endlessh' (No such file or directory) The value of the capability argument is not permitted for a file. Or the file is not a regular (non-symlink) file`

And there is only a empty endlessh.service in /etc/systemd/system/ Instead the non-empty endlessh.service file is in /lib/systemd/system/