We also got this error message after migrating AAA for Cisco IOS, HPE ProVision-based, and HPE Comware-based devices, from CiscoSecure ACS to HPE iMC TACACS Authentication Manager (TAM), by only changing the IP address on the tacacs-server host command. But this error message was only with the PuTTY SSH Client, and only when authenticating to Cisco IOS devices (it did not happen when authenticating to HPE ProVision-based, and HPE Comware-based devices). We got the error message and the PuTTY window suddenly closed. We tried the latest version of PuTTY, and we still got this same error message
After extensive troubleshooting, we concluded that the problem was neither in the Cisco IOS device configuration, nor in HPE iMC. It was just the authentication settings in the SSH client. It seems when integrating Cisco devices with iMC TAM as a TACACS+ server, the keyboard-interactive authentication does not work. You need to change this to password authentication
In PuTTY, the default authentication setting is keyboard-interactive. You can change this by unchecking the Attempt “keyboard-interactive” auth (SSH-2) checkbox under Connection > SSH > Auth (see attachment)
The SSH client from Linux also uses keyboard-interactive authentication by default. However, you can use password authentication with this command:
ssh -o PreferredAuthentications=password <username>@<IP address>
Other SSH clients like F-secure or SecureCRT use password authentication by default, so we don’t have this problem with them
