systemctl status最近更新后，我的 18.04 服务器由于两个单元发生故障而处于降级状态（如 所报告）。/var/log/syslog我每 90 秒收到以下几行：
Jun 10 22:07:49 olympus systemd[1]: systemd-resolved.service: Start operation timed out. Terminating.
Jun 10 22:07:49 olympus systemd[1]: systemd-timesyncd.service: Start operation timed out. Terminating.
在journalctl -xe：
-- Unit systemd-timesyncd.service has failed.
--
-- The result is RESULT.
jun 10 22:22:52 olympus systemd[1]: systemd-resolved.service: Failed with result 'timeout'.
jun 10 22:22:52 olympus systemd[1]: Failed to start Network Name Resolution.
systemctl status systemd-timesyncd表明它Active (activating)始终存在：
● systemd-timesyncd.service - Network Time Synchronization
Loaded: loaded (/lib/systemd/system/systemd-timesyncd.service; enabled; vendor preset: enabled)
Active: activating (start) since Mon 2019-06-10 22:34:54 CEST; 1min 4s ago
Docs: man:systemd-timesyncd.service(8)
Main PID: 14410 ((imesyncd))
Tasks: 1 (limit: 4302)
CGroup: /system.slice/systemd-timesyncd.service
└─14410 (imesyncd)
jun 10 22:34:54 olympus systemd[1]: Starting Network Time Synchronization...
1 分 30 秒后，它会放弃并重新启动。 同样也是如此systemd-resolvd。
除此活动（以及它生成的大量消息）之外，服务器似乎运行良好。
这些设备到底出了什么问题？我该如何调试这个问题？
/etc/netplan/编辑：请求的命令的输出。 中和 中都没有任何内容/etc/network/interfaces.d/。
jos@olympus:~$ ls -al /etc/resolv.conf
-rw-r--r-- 1 root root 65 jan 30 09:46 /etc/resolv.conf
jos@olympus:~$ cat /etc/resolv.conf
nameserver 192.168.124.254
nameserver 8.8.8.8
nameserver 8.8.4.4
jos@olympus:~$ ls /etc/netplan
jos@olympus:~$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto enp4s0
iface enp4s0 inet static
address 192.168.124.99
netmask 255.255.255.0
gateway 192.168.124.254
dns-nameservers 192.168.124.254 213.75.63.75 213.75.63.76 8.8.8.8 8.8.4.4