Telnet Failed

dellpe

Recently received two new switches, model S5700-28C-SI (V200R001C00), I've tried configure the authentication-mode password user the user-interface vty.
However , the telnet fail but telnet will be successful if the authentication mode is aaa.
Below are the config:
#
user-interface con 0
user-interface vty 0 4
authentication-mode password
user privilege level 1
user-interface vty 16 20
#


While debugging vty negotiate, the error "EXEC do not support null authentication-mode".
Is there any issue with this switch or my configuration have problem?

elderkai

You have authentication-mode set to password, but with no password set on the vty.