RT AC-68U OpenVpn

[margiel]

Hello,

I've got configuration my vpn like this:
# Automatically generated configuration
daemon ovpn-server1
topology subnet
server 192.168.2.0 255.255.255.0
proto udp
port 1194
dev tun21
txqueuelen 1000
ncp-ciphers AES-128-GCM:AES-256-GCM:AES-128-CBC:AES-256-CBC
cipher AES-256-CBC
auth SHA256
comp-lzo adaptive
keepalive 15 60
verb 3
push "route 192.168.1.0 255.255.255.0 vpn_gateway 500"
client-config-dir ccd
client-to-client
ccd-exclusive
route 192.168.2.2 255.255.255.0
route 192.168.2.11 255.255.255.0
route 192.168.2.3 255.255.255.0
route 192.168.2.4 255.255.255.0
route 192.168.2.5 255.255.255.0
route 192.168.2.2 255.255.255.0
push "dhcp-option DNS 192.168.1.1"
push "redirect-gateway def1"
ca ca.crt
dh dh.pem
cert server.crt
key server.key
script-security 2
up updown.sh
down updown.sh
status-version 2
status status 5

# Custom Configuration

When I add 7th postion into Allowed Clients and press Apply the cofiguration will be automatically change and then:
Two lines deleted:
push "dhcp-option DNS 192.168.1.1"
push "redirect-gateway def1"

Two new lines added:
route 192.168.2.7 255.255.255.0
tls-auth static.key 0

And after that I cannot connect to the VPN because because I have an error on vpn server side:
TLS Error: cannot locate HMAC in incoming packet from
I try to make modification inside the config.ovpn manually and restart the vpn but config.ovpn is created automatically with the same result.

Do you have any idea what is the reason ?
Why 7th position cause strange change in config file ?