Problem to upedate OpwnWrt 18.06.4 on NEXX WT3020

Hi everyone,
I try to update my OpenWrt 18.06.4 by the browser System--> Software --> Update List, but the system reply to me this:

Downloading http://downloads.openwrt.org/releases/18.06.4/targets/ramips/mt7620/packages/Packages.gz
*** Failed to download the package list from http://downloads.openwrt.org/releases/18.06.4/targets/ramips/mt7620/packages/Packages.gz

Downloading http://downloads.openwrt.org/releases/18.06.4/targets/ramips/mt7620/kmods/4.14.131-1-f908844d5e5aab0a4b27f7d4c77655d0/Packages.gz
*** Failed to download the package list from http://downloads.openwrt.org/releases/18.06.4/targets/ramips/mt7620/kmods/4.14.131-1-f908844d5e5aab0a4b27f7d4c77655d0/Packages.gz

Downloading http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/base/Packages.gz
*** Failed to download the package list from http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/base/Packages.gz

Downloading http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/luci/Packages.gz
*** Failed to download the package list from http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/luci/Packages.gz

Downloading http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/packages/Packages.gz
*** Failed to download the package list from http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/packages/Packages.gz

Downloading http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/routing/Packages.gz
*** Failed to download the package list from http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/routing/Packages.gz

Downloading http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/telephony/Packages.gz
*** Failed to download the package list from http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/telephony/Packages.gz

Failed to establish connection
Failed to establish connection
Failed to establish connection
Failed to establish connection
Failed to establish connection
Failed to establish connection
Failed to establish connection
Collected errors:
 * opkg_download: Failed to download http://downloads.openwrt.org/releases/18.06.4/targets/ramips/mt7620/packages/Packages.gz, wget returned 4.
 * opkg_download: Check your network settings and connectivity.

 * opkg_download: Failed to download http://downloads.openwrt.org/releases/18.06.4/targets/ramips/mt7620/kmods/4.14.131-1-f908844d5e5aab0a4b27f7d4c77655d0/Packages.gz, wget returned 4.
 * opkg_download: Check your network settings and connectivity.

 * opkg_download: Failed to download http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/base/Packages.gz, wget returned 4.
 * opkg_download: Check your network settings and connectivity.

 * opkg_download: Failed to download http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/luci/Packages.gz, wget returned 4.
 * opkg_download: Check your network settings and connectivity.

 * opkg_download: Failed to download http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/packages/Packages.gz, wget returned 4.
 * opkg_download: Check your network settings and connectivity.

 * opkg_download: Failed to download http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/routing/Packages.gz, wget returned 4.
 * opkg_download: Check your network settings and connectivity.

 * opkg_download: Failed to download http://downloads.openwrt.org/releases/18.06.4/packages/mipsel_24kc/telephony/Packages.gz, wget returned 4.
 * opkg_download: Check your network settings and connectivity.

Why I can't update the system? I try by SSH but have the same REPLY.
Thanks

See https://openwrt.org/faq/failed_to_download_wget_returned_4

You tink is for the internect proxy or firewall??