Hello Ivan, thanks for your reply. > cat /etc/sysconfig/network/ifcfg-eth0 > BOOTPROTO='dhcp' > MTU='' > REMOTE_IPADDR='' > STARTMODE='onboot' > uname -a > Linux localhost 5.3.18-lp152.78-lpae #1 SMP Tue Jun 1 14:53:21 UTC 2021 (556d823) armv7l armv7l armv7l GNU/Linux Now this problem still happens. Is my Raspberry Pi broken? Let me update the system / Switch back again to Raspbian to see.