Written 6 Sep 2026. This is a how-to, not a product card.

When casting won't find the TV

Phone or laptop can't see Chromecast, AirPlay, or the smart TV after Pi-hole. Same Wi-Fi first, pause blocking to prove it, then allow the blocked name. You don't need a new TV.

Haven't installed the house ad block yet? Start with the first useful thing. A normal website broke instead of the cast picker? That walk is when a site won't load after Pi-hole. You already know the domain and just want it allowed? That is allow a site in Pi-hole on purpose. This note is the cast/AirPlay picker that stays empty, or the TV that never appears on the phone.

Skip until phone and TV share one network

Casting needs the phone and the TV (or stick) on the same house Wi-Fi. Guest Wi-Fi, a travel hotspot, cellular data, and “AP isolation” / client isolation on the router all hide the TV even when Pi-hole is perfect. Put the phone on the main house SSID. Put the TV on that same SSID (not guest). Turn off the phone VPN for a minute. Guest Wi-Fi still showing ads for visitors is a different job: when guest Wi-Fi still shows ads.

What this is

Two different failures get blamed on Pi-hole. One is DNS: a block list catches a Google, Apple, Roku, or Amazon name the cast app needs, so the phone never finishes talking to the maker cloud or the stick. The other is discovery on the house network (mDNS / Bonjour / SSDP). Pi-hole does not route that traffic. Same Wi-Fi and no client isolation fix discovery. The pause test below tells you which failure you have.

Step 1: prove whether Pi-hole is involved

On the phone, open the cast or AirPlay picker once so it fails the usual way. Then pause blocking for five minutes from the computer over SSH:

pihole disable 5m

Try casting again while blocking is off. Blocking turns itself back on after five minutes. Turn it on sooner when you are done:

pihole enable

Same idea in the admin page: open http://pi.hole/admin (or the computer's address plus /admin), find Disable blocking, pick five minutes. Admin page blank? When the Pi-hole admin page won't open. Forgot the admin password? Change the Pi-hole admin password.

If casting works only while blocking is off, Pi-hole is involved. Keep going. If casting still fails with blocking off, leave the block list alone. Fix same Wi-Fi, client isolation, or the TV's own network settings first. Ads back house-wide is still when ads come back.

Step 2: catch the blocked name

With blocking on again, open Query Log in the admin page. On the phone, open the cast picker once more so fresh rows appear. Look for blocked names around that moment. From SSH you can watch live:

pihole tail

Press Ctrl-C when you have a name. Copy the exact host (like a *.google.com or maker CDN name), not a full URL. Guessing a long allow list is how you open trackers for the whole house. Prefer one name from the log. Calmer look anytime: see what Pi-hole blocked.

Step 3: allow that one domain

SSH into the computer, then:

pihole allow example.com

Swap in the real name from the log. Or open Domains in the admin page and add it on the allow / whitelist side. From Query Log you can often open a row and choose Allow. Either path is fine. Full calm allow walk: allow a site in Pi-hole on purpose.

Step 4: prove the cast again

On the phone, close the cast picker, wait a few seconds, open it again. Toggle Wi-Fi off and on once if the TV still hides (sticky DNS cache on the phone). In Query Log the name should show as allowed / OK when the phone asks. If casting still fails, watch the log again and allow the next exact blocked name for that try. Stop when the TV appears. Don't allow every Google or Apple name “just in case.”

If you allowed the wrong thing

Open Domains in the admin page and remove that name from the allow list. Prefer removing one bad allow over leaving blocking off. A five-minute pause is for diagnosis. A permanent disable is how ads come back for everyone.

What this is not

This is not a reason to buy a new Chromecast, a new TV, or a mesh kit. It is not opening the Pi-hole admin page past the house network. It is not fixing a phone that uses Private DNS, Private Relay, or a VPN that bypasses house DNS for browsing (that walk is when one phone still shows ads). It is not guest Wi-Fi by design. Discovery across two SSIDs is a router setting problem, not a Pi-hole allow list.

What next

Leave the allow list alone when casting works. Printer vanished from the phone? That is when the printer won't print. For a bank or login that breaks the same way, see when a site won't load after Pi-hole. For a calmer allow when you already know the domain, see allow a site in Pi-hole on purpose. Once a week, keep Pi-hole updated. Before a scary reinstall, save a Pi-hole backup so your allow entries survive. A file share on this same computer can wait: a file share.

Optional: jot that casting works again in Lab plan — username + passkey, no email. Skip if you just want to keep reading.

Skip

• Skip buying a new TV or stick for this.
• Skip leaving blocking disabled overnight.
• Skip allowing every name in the log “just in case.”
• Skip wildcards and regex on day one.
• Skip opening the Pi-hole admin page to the internet.
• Skip casting from guest Wi-Fi or cellular and blaming Pi-hole.
• Skip a mesh kit or a new router for one allow entry.