Android 2 device does Wi-fi. Can't L2TP/Ipsec.

[n-harada]

Devices:
pfSense 2.2.4
iOS 8.4.1
Android 5.0.2
Ubuntu 12.04.5 (apt-get install l2tp-ipsec-vpn)

I set up URL.
L2TP/IPsec on Android
https://doc.pfsense.org/index.php/L2TP/IPsec_on_Android

It is failed by the L2TP/IPsec connection from the Wi-Fi access point.
Combinations are connected with each other.

single:
OK iOS
OK Android
OK Ubuntu

Combinations:
OK iOS iOS
OK iOS Android
OK iOS Ubuntu
NG Android Android
NG Android Ubuntu
NG Ubuntu Ubuntu

Android and Ubuntu will fail in L2TP.

Competition of L2TP regards me as a cause.
L2TP port:
OS source destination
iOS variably 1701
Android 1701 1701
Ubuntu 1701 1701

I was able to put it together when I did L2TP of Ubuntu variably.
L2TP port:
OS source destination
Ubuntu variably 1701

Combinations:
NG Android Android
OK Android Ubuntu
OK Ubuntu Ubuntu

But, Android is not made in variableness in L2TP.
Can it be settled on the pfSense side?