Here is a diagram of my setup below:
Is this forward rule (12) I have added correct? When I ping the DMZ I get timeout.
[admin@NolliTik] > /ip/firewall export
# jan/17/2022 11:50:26 by RouterOS 7.1
# software id = 33B2-XGBT
#
# model = RB450Gx4
# serial number = ADBA0ACE537B
/ip firewall address-list
add address=10.0.8.0/24 list=nolliLAN-management
add address=10.8.27.0/24 list=DMZPBX
/ip firewall filter
add action=accept chain=input comment="defconf: accept established,related,untracked" connection-state=established,related,untracked
add action=drop chain=input comment="defconf: drop invalid" connection-state=invalid
add action=accept chain=input src-address-list=nolliLAN-management
add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
add action=accept chain=input comment="defconf: accept to local loopback (for CAPsMAN)" dst-address=127.0.0.1
add action=drop chain=input comment="defconf: drop all not coming from LAN" in-interface-list=!LAN
add action=accept chain=forward comment="defconf: accept in ipsec policy" ipsec-policy=in,ipsec
add action=accept chain=forward comment="defconf: accept out ipsec policy" ipsec-policy=out,ipsec
add action=fasttrack-connection chain=forward comment="defconf: fasttrack" connection-state=established,related hw-offload=yes
add action=accept chain=forward comment="defconf: accept established,related, untracked" connection-state=established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" connection-state=invalid
add action=accept chain=forward comment="Allow admin to manage DMZ" dst-address-list=DMZPBX src-address-list=nolliLAN-management
add action=drop chain=forward comment="defconf: drop all from WAN not DSTNATed" connection-nat-state=!dstnat connection-state=new in-interface-list=WAN
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" ipsec-policy=out,none out-interface-list=WAN
[admin@NolliTik] > ping 10.8.27.9
SEQ HOST SIZE TTL TIME STATUS
0 10.8.27.9 timeout
1 10.8.27.9 timeout
2 10.8.27.9 timeout
3 10.8.27.9 timeout
4 10.8.27.9 timeout
5 10.8.27.9 timeout
6 10.8.27.9 timeout
sent=7 received=0 packet-loss=100%
[admin@NolliTik] >