Duo Authentication Proxy not working with Passcode

Client is using DUO Cloud as the Primary Authentication source using Duo Auth Proxy. So, 2FA is happening before the actual authentication with ISE. We have put [duo_only_client] in authproxy.cfg. This process is working fine if we put push in the Password-1, end user receives a Push notification and he is able to proceed further. But when he types Passcode in Password-1, he receives a Push notification and the judgement is made using Push and not Passcode.

Where should we make changes for this setup to accept passcode?

[radius_server_auto50]
ikey=xxxxxxx
skey=xxxxxxxx
api_host=xxxxxxxx
radius_ip_2=xx.xx.xx.xxx
radius_secret_2=radiussecretXXX
client=duo_only_client
port=18126
failmode=safe

[duo_only_client]