After Updating ubuntu, web console not working

[madscientist]

i have a multi server with 20 ip camera test setup using ubuntu 18.04, one database server, three zm server, and shared nfs storage to store events, every thing going perfect, but two days ago i just updated all these three server with only two command, apt-get update and apt-get distupgrade, after that zoneminder service is working fine, recording events, but i am unable to view the zoneminder console/web page to view, all stopped, showing "This page isn’t working192.168.137.62 is currently unable to handle this request.
HTTP ERROR 500", i am also attaching the status of zoneminder here : -
root@zm3:~# systemctl status zoneminder.service
● zoneminder.service - ZoneMinder CCTV recording and surveillance system
Loaded: loaded (/lib/systemd/system/zoneminder.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2020-12-21 18:07:17 IST; 22h ago
Process: 1023 ExecStart=/usr/bin/zmpkg.pl start (code=exited, status=0/SUCCESS)
Main PID: 1280 (zmdc.pl)
Tasks: 8 (limit: 4915)
CGroup: /system.slice/zoneminder.service
├─1280 /usr/bin/perl -wT /usr/bin/zmdc.pl startup
├─1387 /usr/bin/perl -wT /usr/bin/zmwatch.pl
├─1392 /usr/bin/perl -wT /usr/bin/zmupdate.pl -c
├─1404 /usr/bin/perl -wT /usr/bin/zmstats.pl
├─5105 /usr/bin/perl -wT /usr/bin/zmtelemetry.pl
├─5117 /usr/bin/perl -wT /usr/bin/zmfilter.pl --filter_id=2 --daemon
├─5252 /usr/bin/perl -wT /usr/bin/zmfilter.pl --filter_id=1 --daemon
└─7950 /bin/rm -rf /var/cache/zoneminder/events/11/2020-12-17/267363

Dec 22 16:47:02 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:10 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:20 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:25 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:28 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:33 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:37 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:45 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:52 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind
Dec 22 16:47:57 zm3 zmfilter_2[5117]: WAR [DiskSpace: Event does not exist at /var/cache/zonemind

kindly help. not able to figure out what went wrong ?
thanks'

[Magic919]

I can't see anyone else working this out for you.

Check the logs, turn on debug, do some troubleshooting.

Sounds like ZM is running. That has no bearing on the webUI, so sort that bit out first and go from there.