Rui,
To be clear a router does not set up a "Static IP address" in the U22
What it does is reserve an IP address (using DHCP reservation) for a specific MAC address ( ie in this case the U22) so the U22 always gets this address when using DHCP
@ICF9
as you have said that the media files play fine from a USB stick connected directly using different players is unlikely to be of any use benefit
Your issues point either to a "faulty" network device in the U22 itself, or in the network configuration of your LAN
Do as i suggested in post #33 with your U22 connected via ethernet direct to your router