OpenVPN: Authentication Failed? - server-side

Question

When I use the plugin for authentication at server.conf, authentication wont work, but without it, non existent users can authenticate also.
I have added the following lines in the server conf and clinet
Commands in the server.conf file
================================
mode server
tls-server
plugin /usr/lib64/openvpn/plugin/lib/openvpn-auth-pam.so login
key-direction 0
================================
Commands in the client file
=================================
port 1194
proto udp
dev tun
nobind
key-direction 1
redirect-gateway def1
tls-version-min 1.2
auth SHA256
auth-user-pass
tls-client
remote-cert-tls server
resolv-retry infinite
persist-key
persist-tun
verb 3
===============================
Logs:
==============================================================
PLUGIN_CALL: POST /usr/lib64/openvpn/plugin/lib/openvpn-auth-pam.so/PLUGIN_AUTH_USER_PASS_VERIFY status=1
PLUGIN_CALL: plugin function PLUGIN_AUTH_USER_PASS_VERIFY failed with status 1: /usr/lib64/openvpn/plugin/lib/openvpn-auth-pam.so
TLS Auth Error: Auth Username/Password verification failed for peer
Authenticate/Decrypt packet error: bad packet ID (may be a replay): [ #7 / time = (1559124952) Wed May 29 10:15:52 2019 ] -- see the man page entry for --no-replay and --replay-window for more info or silence this warning with --mute-replay-warnings
TLS Error: incoming packet authentication failed from [AF_INET6]::ffff:
openvpn[10420]: pam_unix(login:auth): authentication failure; logname= uid=0 euid=0 tty= ruser= rhost= user=*****```
==============================================================

Answer 1

I have used differen approached, although in production plugin /usr/lib64/openvpn/plugin/lib/openvpn-auth-pam.so login is recommended way, but I have taken one shell script and got authentication, but remember it is dangerous.
add following lines in your /etc/openvpn/server.conf file
--verify-cline-cert none
script-security 2
auth-user-pass-verify /etc/openvpn/example.sh via-file
Now create a file in /etc/openvpn/example.sh with following content
!/bin/bash
echo "started"
username=`head -1 $1`
password=`tail -1 $1`
if grep "$username:$password" $0.passwd > /dev/null 2>&1
then
exit 0
else
if grep "$username" $0.passwd > /dev/null 2>&1
then
echo "auth-user-pass-verify: Wrong password entered for user '$username'"
else
echo "auth-user-pass-verify: Unknown user '$username'"
fi
exit 1
fi
Now create username and password in /etc/openvpn/example.sh.passwd with following content
userone:securepassworduserone
usertwo:securepasswordusertwo
Now create a client file and import and connect using your password, but this where I am stack as I don't want to provide client file.