One of our Debian servers had a large time discrepancy. Turned out NTP wasn’t installed or working. After I installed ntp I still wasn’t seeing a time update. Probably because I was more than 30 minutes adrift. So I had to force an ntp update. Install ntp and set the servers in the .conf to match your ntp servers.
$ sudo apt-get install ntp
$ sudo vi /etc/ntp.confThen force a time update
$ sudo systemctl stop ntp.service
$ sudo ntpd -gq
$ sudo systemctl start ntp.serviceThe ntpd may take a while before dropping you back to the prompt.