Admin fix: of I get DNS resolution errors

Occasionally your router and the device fail to agree on DNS services and this can happen even if things were fine before. This is happening mostly on WLAN connections, thus you should try to see if a wired connection fixes the issue. If you must stay on WLAN solution then contact us as the fix will require some handholding either with us of Jetvision

First port of call is to set the dns to google

sudo resolvectl dns wlan0 8.8.8.8 && sudo resolvectl domain wlan0 "~."

in one case we had to disable dnssec

sudo resolvectl dnssec wlan0 no

But it's a bad ides. Best one is to add tosudo nano /etc/systemd/resolved.conf

#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
#
# See resolved.conf(5) for details

[Resolve]
DNS=1.1.1.1
DNSOverTLS=opportunistic
DNSSEC=yes
#DNS=
#FallbackDNS=
#Domains=
#LLMNR=yes
#MulticastDNS=yes
#DNSSEC=allow-downgrade
#DNSOverTLS=no
#Cache=yes
#DNSStubListener=yes
#ReadEtcHosts=yes

and then sudo systemctl restart systemd-resolved