Error! No parameter given. when using the telnet auth option

[michelpy]

If the 'telnet' auth option is used for a router (Cisco 4300), I get this error message :
Error! No parameter given.
It works when the 'ssh-password' auth option is used.
It does not matter if the 'cisco' or 'ios' option is used in router type, probably the issue is with the telnet option itself.

[gmazoyer]

This means that the response is either an empty string or invalid. The root cause may not come from your device but from the way telnet is handle. It's managed in a generic way a known to be broken for a number of platforms.

The telnet code should be removed from the code base, or be rewritten to allow per-platform customisations (which would take a significant amount of time).