Problem with network in Beelink GT1 Ultimate running Kodi 17.3

I have a strange issue in my Beelink GT1 Ultimate Android box running Kodi 17.3
In my home network I have set up three kodi 17.3.
1. In Win10 – network works ok
2. In Xperia M5 smartphone running Android 6.0 – network works ok
3. In Android TV Box Beelink GT1 Ultimate – extremely slow connection

All in the same network with VDSL connection

Android TV Box Beelink GT1 Ultimate with the following specs:
DEVICE: Beelink GT1 Ultimate
Build: GT1_313MO
Android security patch level: August 1, 2015 Version: 6.0.1
Kodi 17.3 GIT: 20170524-147CEC4 Compiled: May 24 2017

VDSL Router:
Manufacturer:ZTE;
ProductClass:ZXHN H367N;
SerialNumber:***********768;
IP:192.168.2.1;
HWVer:V1.4.0;
SWVer:V1.0.2_LR_VDF

Network Settings:
Use DHCP
In System Info->NETWORK, indicates MAC ADDRESS: Busy, Internet: Busy but after a few seconds everything works ok (indicates CONNECTED)
Note that Gateway field is empty. But same happens in my in Xperia M5 phone that works ok

– Internet outside Kodi works ok (youtube, chrome etc)
– I tested the TV BOX in other Router/Connection and works ok
– In the TV box Kodi cannot even fetch the weather providers.

The question is why my two other devices work ok with kodi and not in the TV Box. Is there a setting in my router??
Any hints??
Thanks