Target disk space check failure while flashing by SDK Manager

What do you get with ifconfig on your host PC when you get stuck at this?

RTNETLINK answers: File exists

At the moment, when the SDK Manager shows RTNETLINK answers: File exists, the ifconfig shows three interfaces. The network interface which is connected to the internet, a loopback interface (lo) and a USB interface. Here is the output for the USB interface:

usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet6 fc00:1:1::1  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::2c6f:62ff:febf:234b  prefixlen 64  scopeid 0x20<link>
        inet6 fe80::2  prefixlen 128  scopeid 0x20<link>
        ether 2e:6f:62:bf:23:4b  txqueuelen 1000  (Ethernet)
        RX packets 10  bytes 848 (848.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Maybe it’s about firewall or stuff like that.
Or you can try this: