Invalid Input '^' while doing portforward in cisco router

I am using Open VPN and able to access it internally. Now to access it from outside, I am trying to do a port forward on Cisco Configuration Professional Express.

I am logging into cisco console using Putty.

After refering to few posts , I came up with this command:

ip nat inside source static tcp 10.0.0.143 443 <EXTERNAL_IP> 443

But as soon as I execute this command, I am getting this error,

% Invalid input detected at '^' marker.

Error screen,