Can't connect to TFTP

Guys please help me.
I’m trying to upload a new u-boot. But the thing doesn’t connects.
Ethernet is working, cable is ok and it’s visible from linux.
But from within uboot it doesn’t work!
I’ve tried different ip addresses - no luck!

kvim2#setenv ipaddr 10.0.0.100
kvim2#setenv serverip 10.0.0.50
kvim2#ping 10.0.0.50
dwmac.c9410000 Waiting for PHY auto negotiation to complete... done
Speed: 100, full duplex
Using dwmac.c9410000 device
ping failed; host 10.0.0.50 is not alive

and on server:

en9: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	options=10b<RXCSUM,TXCSUM,VLAN_HWTAGGING,AV>
	ether 68:5b:35:bd:c1:6c 
	inet 10.0.0.50 netmask 0xffffff00 broadcast 10.0.0.255
	nd6 options=201<PERFORMNUD,DAD>
	media: 100baseTX <full-duplex,flow-control> (none)
	status: inactive

and notice server interface status after doing “reset” and booting vim to linux:

en9: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	options=10b<RXCSUM,TXCSUM,VLAN_HWTAGGING,AV>
	ether 68:5b:35:bd:c1:6c 
	inet 10.0.0.50 netmask 0xffffff00 broadcast 10.0.0.255
	inet6 fe80::14b4:370d:5a2e:bb5b%en9 prefixlen 64 secured scopeid 0x12 
	inet 172.31.255.10 netmask 0xffffff00 broadcast 172.31.255.255
	nd6 options=201<PERFORMNUD,DAD>
	media: 100baseTX <full-duplex,flow-control>
	status: active

Why?!!

U-Boot 2015.01 (May 31 2018 - 16:40:12)

Hello kkkkk,

Which image you used?