Authentication Error when i switch from user exec to privi mode

[arouna.kikone1]

help me

I can't access my cisco router.
after enabling ssh and authentication, i forgot to enable authorization on the router.
when I connect to the router and want to switch from "user exec mode" to "privileged EXEC mode", I get this error "% Error in Authentication".
How to solve this problem? need your expertise.

[Flavio Miranda]

Hi @arouna.kikone1 

 You are going to need console connection to the device. Using remote access you can not fix it.

[arouna.kikone1]

@Flavio Miranda I tried the console connection but the problem persists.

I have the same error "% Error in Authentication".

[Flavio Miranda]

Do you have any show running config saved?

Seems console is configured with tacacs , which is a terrible idea.

 Probably you need to factory reset the switch

[arouna.kikone1]

@Flavio Miranda unfortunately I don't have the latest config after making the changes to the authentication.
But after having configured the access by ssh, configured the username and password; I remember adding the following commands:

aaa new-model
aaa authentication enable default enable
aaa authentication login default local
aaa authentication login default local-case

[Flavio Miranda]

Unfortunatelly does not matter now. You locked yourself outside.

 You need to factory reset the device.

[UZaman3]

What model router is it? You may be able to do a password break. See link below for a Cisco ISR. You might be able to do something similar where you boot into rommon mode and bypass the startup-config.

https://www.cisco.com/c/en/us/td/docs/routers/access/4400/troubleshooting/guide/isr4400trbl/isr4400trbl02.pdf

[arouna.kikone1]

@UZaman3 it is an ISR4351/K9 router.
it's a router that is in production and resetting the device will create a lot of inconvenience. I'll try to follow the document you sent me in order to break the password.