It can not set ip address automatical in openvpn link

[krwy0330]

Hi everyone:

I use asus RT-AC86U to link NETGEAR R6400 with openvpn

Then I export the .ovpn from NETGEAR R6400 as follows

client
dev tap
proto udp
remote xxx.mynetgear.com 12974
resolv-retry infinite
nobind
persist-key
persist-tun
ca ca.crt
cert client.crt
key client.key
cipher AES-128-CBC
comp-lzo
verb 5

I use RT-AC86U(powered by asuswrt-merlin 384.8_2) to connect it successfully.

However, RT-AC86U can not set an ip address automatically.
I should use command "ip addr add" to add address by manual.
Does anyone know how to fix it?
This is the log from the client of openvpn.

Jan 19 12:44:04 ovpn-client1[12972]: SENT CONTROL [netgear]: 'PUSH_REQUEST' (status=1)
Jan 19 12:44:09 ovpn-client1[12972]: SENT CONTROL [netgear]: 'PUSH_REQUEST' (status=1)
Jan 19 12:44:15 ovpn-client1[12972]: SENT CONTROL [netgear]: 'PUSH_REQUEST' (status=1)
Jan 19 12:44:15 ovpn-client1[12972]: PUSH: Received control message: 'PUSH_REPLY,route 192.168.198.1 255.255.255.0 192.168.198.1,route-gateway dhcp,ping 10,ping-restart 120'
Jan 19 12:44:15 ovpn-client1[12972]: OPTIONS IMPORT: timers and/or timeouts modified
Jan 19 12:44:15 ovpn-client1[12972]: OPTIONS IMPORT: route options modified
Jan 19 12:44:15 ovpn-client1[12972]: OPTIONS IMPORT: route-related options modified
Jan 19 12:44:15 ovpn-client1[12972]: Data Channel MTU parms [ L:1590 D:1450 EF:58 EB:411 ET:32 EL:3 ]
Jan 19 12:44:15 ovpn-client1[12972]: Outgoing Data Channel: Cipher 'AES-128-CBC' initialized with 128 bit key
Jan 19 12:44:15 ovpn-client1[12972]: Outgoing Data Channel: Using 160 bit message hash 'SHA1' for HMAC authentication
Jan 19 12:44:15 ovpn-client1[12972]: Incoming Data Channel: Cipher 'AES-128-CBC' initialized with 128 bit key
Jan 19 12:44:15 ovpn-client1[12972]: Incoming Data Channel: Using 160 bit message hash 'SHA1' for HMAC authentication
Jan 19 12:44:15 ovpn-client1[12972]: TUN/TAP device tap11 opened
Jan 19 12:44:15 ovpn-client1[12972]: TUN/TAP TX queue length set to 100
Jan 19 12:44:15 ovpn-client1[12972]: updown.sh tap11 1500 1590   init
Jan 19 12:44:17 ovpn-client1[12972]: /bin/ip route add 192.168.198.1/24 via 192.168.198.1
Jan 19 12:44:17 ovpn-client1[12972]: ERROR: Linux route add command failed: external program exited with error status: 2
Jan 19 12:44:17 ovpn-client1[12972]: WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this
Jan 19 12:44:17 ovpn-client1[12972]: Initialization Sequence Completed

Thanks