Help needed to get DHCP and DNS working correctly!

fin1000

Have been trying to sort this DNS problem out for months but nothing will get my devices connected to my VPN gateway to use the servers set in general settings
Anything connected to the VPN (VL20_VPN ) uses the ISP DNS server.
When the system was built more than 5 years ago it worked fine but sometime something changed.

I have WAN, LAN(not used) virtual networks VL10_MGT - VL20_VPN - VL30_CLRNET - VL40_GUEST and VPN_WAN

Using DHCP SERVER- no DNS set except on VL40_GUEST (which works as it should and uses the set DCHP DNS)
Using DNS servers if set in the DCHP SERVER setting for the VL20_VPN does not work and still uses the ISP DNS

DNS resolver set to
Network interfaces
LAN, VL10_MGT, VL20_VPN, Localhost

Outgoing interfaces
VPN_WAN

CUSTOM
local-data: “local.lan 10800 IN SOA
pfsense.local.lan. root.local.lan. 1 3600 1200
604800 10800”

DNS forwarder
Interfaces Localhost

Domain override 10.0.in.addr.arpa.
ip 10.0.20.1 reverse forwarder

General settings two dns addresses set
and default 127.0.0.1

What am I doing wrong?

Additionally, when using Firefox or Brave and setting custom DNS using 1.1.1.1 or any other numeric address dns lookup fails
If set via the named ones like opendns the browsers dns is working
As I’m getting problems on Pfsense with DNS
can this be linked?
Obviously the browsers get the dns server to work internally from the name in the box it just won’t work with 8.8.8.8 or 1.1.1.1 etc
Could this also be some ISP blocking other DNS servers? Tho it’s happening on Comcast in US and BT in Uk (identical systems except isp) (my computers are all Linux )