I just wanted to leave this here in case anyone runs into the same or similar issue.
I just installed and updated Pi-Hole.
(At the time of writing this, versions were Pi-Hole V5.11.4, FTL V5.16.1, Web Interface V5.13)
Followed the online instructions to install Unbound.
The problem starts here. Unbound not allowing mobile device to connect to the internet.
I ran
dig pi-hole.net @127.0.0.1 -p 5335
got back
; <<>> DiG 9.16.27-Raspbian <<>> pi-hole.net @127.0.0.1 -p 5335
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 21576
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;pi-hole.net. IN A
;; Query time: 10 msec
;; SERVER: 127.0.0.1#5335(127.0.0.1)
;; WHEN: Sun Jul 31 22:54:54 BST 2022
;; MSG SIZE rcvd: 40
Then I ran the following to check what was running on port the Pi-Hole ports.
sudo netstat -nltup | grep 'Proto\|:53 \|:5053 \|:5353 \|:5335 \|:8953 \|:67 \|:80 \|:471'
Got back
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:4711 0.0.0.0:* LISTEN 1467/pihole-FTL
tcp 0 0 127.0.0.1:5335 0.0.0.0:* LISTEN 1505/unbound
tcp 0 0 127.0.0.1:8953 0.0.0.0:* LISTEN 1505/unbound
tcp 0 0 0.0.0.0:53 0.0.0.0:* LISTEN 1467/pihole-FTL
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 564/lighttpd
tcp6 0 0 :::53 :::* LISTEN 1467/pihole-FTL
tcp6 0 0 ::1:4711 :::* LISTEN 1467/pihole-FTL
tcp6 0 0 :::80 :::* LISTEN 564/lighttpd
udp 0 0 0.0.0.0:53 0.0.0.0:* 1467/pihole-FTL
udp 0 0 0.0.0.0:67 0.0.0.0:* 1467/pihole-FTL
udp 0 0 127.0.0.1:5335 0.0.0.0:* 1505/unbound
udp 0 0 0.0.0.0:5335 0.0.0.0:* 246/avahi-daemon: r
udp6 0 0 :::53 :::* 1467/pihole-FTL
udp6 0 0 :::5335 :::* 246/avahi-daemon: r
As you can see, the avahi-deamon was running on #5335 as well. The fix for this was simple. I just changed the listen port to #5334 under Settings > Upstream DNS Servers to #5334.
Then I ran
sudo service unbound restart
After that the wifi on my mobile devices locked in right away.
Hope someone finds this useful. Be well.