Ok, nothing there other than @fullzero's USB reference (comment out last 2 lines of /etc/fstab to fix those mount timeout errors). Anyway, let's try another tact. Can you find anything related to the time when it last happened using:
journalctl -u NetworkManager
that should give you detailed networking information.
Networkmanager - disabled.
Syslog from another rig
WARNING **: log file empty (logrotate?) /var/log/apt/term.log
Nov 6 06:40:18 m1-desktop AptDaemon: INFO: Quitting due to inactivity
Nov 6 06:40:18 m1-desktop org.debian.apt[554]: 06:40:18 AptDaemon [INFO]: Quitting due to inactivity
Nov 6 06:40:18 m1-desktop org.debian.apt[554]: 06:40:18 AptDaemon [INFO]: Quitting was requested
Nov 6 06:40:18 m1-desktop AptDaemon: INFO: Quitting was requested
Nov 6 07:17:01 m1-desktop CRON[10281]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Nov 6 07:30:01 m1-desktop CRON[12570]: (root) CMD (test -x /etc/init.d/anacron && /usr/sbin/invoke-rc.d anacron start >/dev/null)
Nov 6 07:30:01 m1-desktop anacron[12592]: Anacron 2.3 started on 2017-11-06
Nov 6 07:30:01 m1-desktop anacron[12592]: Will run job `cron.daily' in 5 min.
Nov 6 07:30:01 m1-desktop anacron[12592]: Jobs will be executed sequentially
Nov 6 07:30:01 m1-desktop systemd[1]: Started Run anacron jobs.
Nov 6 07:31:31 m1-desktop systemd[1]: dev-disk-by\x2duuid-55184403759586FB.device: Job dev-disk-by\x2duuid-55184403759586FB.device/start timed out.
Nov 6 07:31:31 m1-desktop systemd[1]: Timed out waiting for device dev-disk-by\x2duuid-55184403759586FB.device.
Nov 6 07:31:31 m1-desktop systemd[1]: Dependency failed for /mnt/55184403759586FB.
Nov 6 07:31:31 m1-desktop systemd[1]: mnt-55184403759586FB.mount: Job mnt-55184403759586FB.mount/start failed with result 'dependency'.
Nov 6 07:31:31 m1-desktop systemd[1]: dev-disk-by\x2duuid-55184403759586FB.device: Job dev-disk-by\x2duuid-55184403759586FB.device/start failed with result 'timeout'.
Nov 6 07:31:31 m1-desktop systemd[1]: dev-disk-by\x2did-usb\x2dSanDisk_Cruzer_Blade_4C530001260812105231\x2d0:0\x2dpart1.device: Job dev-disk-by\x2did-usb\x2dSanDisk_Cruzer_Blade_4C530001260812105231\x2d0:0\x2dpart1.device/start timed out.
Nov 6 07:31:31 m1-desktop systemd[1]: Timed out waiting for device dev-disk-by\x2did-usb\x2dSanDisk_Cruzer_Blade_4C530001260812105231\x2d0:0\x2dpart1.device.
Nov 6 07:31:31 m1-desktop systemd[1]: Dependency failed for /mnt/usb-SanDisk_Cruzer_Blade_4C530001260812105231-0:0-part1.
Nov 6 07:31:31 m1-desktop systemd[1]: mnt-usb\x2dSanDisk_Cruzer_Blade_4C530001260812105231\x2d0:0\x2dpart1.mount: Job mnt-usb\x2dSanDisk_Cruzer_Blade_4C530001260812105231\x2d0:0\x2dpart1.mount/start failed with result 'dependency'.
Nov 6 07:31:31 m1-desktop systemd[1]: dev-disk-by\x2did-usb\x2dSanDisk_Cruzer_Blade_4C530001260812105231\x2d0:0\x2dpart1.device: Job dev-disk-by\x2did-usb\x2dSanDisk_Cruzer_Blade_4C530001260812105231\x2d0:0\x2dpart1.device/start failed with result 'timeout'.
Nov 6 07:35:01 m1-desktop anacron[12592]: Job `cron.daily' started
Nov 6 07:35:01 m1-desktop anacron[13336]: Updated timestamp for job `cron.daily' to 2017-11-06
Nov 6 07:35:01 m1-desktop cracklib: no dictionary update necessary.
Nov 6 07:35:01 m1-desktop rsyslogd: [origin software="rsyslogd" swVersion="8.16.0" x-pid="553" x-info="http://www.rsyslog.com"] rsyslogd was HUPed
It looks like problems start after
Nov 6 07:35:01 m1-desktop anacron[12592]: Job `cron.daily' started
Nov 6 07:35:01 m1-desktop anacron[13336]: Updated timestamp for job `cron.daily'
Wait, that is a syslog from a different miner? It looks like you have 2 hosts both with the default name of "m1-desktop". Are they on the same network? If so, that could certainly be a problem.