OpenVPN server process terminates unexpectedly after android client disconnects

I've installed openvpn on a debian VPS & configured it as you see below:

port 1194
proto udp
dev tun
ifconfig 10.0.2.21 10.0.2.22
ifconfig-noexec
route-noexec

keepalive 10 120
persist-key
persist-tun
comp-lzo
verb 3
#fragment 1200
mssfix 1200
#reneg-sec 0

push "dhcp-option DNS 8.8.8.8"
push "dhcp-option DNS 8.8.4.4"

tls-server
tls-auth static.key 0

ca RastakCA.crt
cert ovpn.crt
key ovpn.key
dh ovpn_dh2048.pem

cipher BF-CBC        # Blowfish (default)
cipher AES-128-CBC   # AES
cipher DES-EDE3-CBC  # Triple-DES

status openvpn-status.log
log         openvpn.log
;log-append  openvpn.log

& here is the client config:

client
dev tun
proto udp
remote a.b.c.d
ifconfig 10.0.2.22 10.0.2.21
redirect-gateway def1

tls-client
tls-auth static.key 1 

ca CA.crt
cert ovpn_client.crt
key ovpn_client.key

cipher BF-CBC        # Blowfish (default)
cipher AES-128-CBC   # AES
cipher DES-EDE3-CBC  # Triple-DES

comp-lzo
#fragment 1200
#reneg-sec 0
mssfix 1200
verb 3

now when I connect to it on windows (with openvpn-gui client) everything is OK, but when I use same client config to connect in an android device (using openvpn connect), I get following warning at server side:

Sat Jan 10 22:23:53 2015 WARNING: 'ifconfig' is present in local config but missing in remote config, local='ifconfig 10.0.2.21 10.0.2.22'

& also following error at client side:

Tun interface setup failed: tun_builder_error: one of ifconfig or ifconfig-ipv6 must be specified

I added following line to server config file & I succeed to connect using both windows and android clinets:

push "ifconfig 10.0.2.22 10.0.2.21"

but there is still another problem: when I disconnect manually in android device, server process dies with these lines of log:

Sat Jan 10 23:30:44 2015 TCP/UDP: Closing socket
Sat Jan 10 23:30:44 2015 Closing TUN/TAP interface
Sat Jan 10 23:30:44 2015 SIGTERM[soft,remote-exit] received, process exiting

& I have to restart server daemon again (in the windows client I've no problem after disconnecting manually & also I've no problem with android device when connection loses without disconnecting).
Any solution?