I'm on a symmetric gigabit fiber connection and rarely have issues with most sites. But on YouTube, videos are taking forever to load initially, and then frequently stop to buffer usually never to start playing again.
I've tried on Firefox and Chrome, both with and without browser extensions.
This seems to be new behavior since updating pihole.
Pi-hole v5.3.1
Web Interface v5.5.1
FTL v5.8.1
Expected Behaviour:
YouTube videos should load and play.
Actual Behaviour:
YouTube videos either take minutes to load, or never load.
Apologies if this has nothing to do with the pihole, it's just that YouTube slowing to a crawl and updating pihole seem to have happened right around the same time.
Your debug log is normal and indicates Pi-hole is working properly.
One thing I would change for testing is your upstream DNS provider. You are using Cloudflare, which does not support ECS.
ECS (Extended Client Subnet) defines a mechanism for recursive resolvers to send partial client IP address information to authoritative DNS name servers. Content Delivery Networks (CDNs) and latency-sensitive services use this to give geo-located responses when responding to name lookups coming through public DNS resolvers. Note that ECS may result in reduced privacy.
ECS helps get you IP's that are geographically near you. If you are receiving IP's for YouTube domains that are quite distant, this could cause performance problems.
Look on the admin GUI > Settings > DNS page and select other upstream providers that support ECS. These are indicated in the notes next to each upstream DNS server option.
You aren't on our latest version, which was released a few days ago (after your post). Consider updating to this version after you read the release notes. I don't think there are any changes that may affect your problem, but at least you will be on the latest.