channel 1: open failed: administratively prohibited: open failed
The above message refers to your SSH server rejecting your SSH client's request to open a side channel. This typically comes from -D, -L or -w, as separate channels in the SSH stream are required to ferry the forwarded data across.
Since you are using -L (also applicable to -D), there are two options in question that are causing your SSH server to reject this request:
- AllowTcpForwarding (as Steve Buzonas mentioned)
These options can be found in /etc/ssh/sshd_config. You should check that:
- AllowTCPForwarding is either not present, is commented out, or is set to "yes"
- PermitOpen is either not present, is commented out, or is set to "any"
Additionally, if you are using an SSH key to connect, you should check that the entry corresponding to your SSH key in ~/.ssh/authorized_keys does not have no-port-forwarding or permitopen statements.
Not relevant to your particular command, but somewhat relevant to this topic as well, is the PermitTunnel option if you're attempting to use the -w option.
 Full syntax in the sshd_config(5) manpage.
 Full syntax in the authorized_keys(5) manpage.