BT DNS returns NXDOMAIN for our business domain - all BT customers affected, works on every other IS

briantruongau — Wed, 02 Sep 2026 09:28:20 GMT

Hi all,

Hoping a moderator can help escalate this one, as it's costing us customers.

Our web app at builder.printerp.ai cannot be reached by any of our customers on BT broadband. On every other UK ISP — and on any public DNS — it loads fine. We've confirmed this across multiple separate BT customers on different BT lines.

BT's DNS returns "Non-existent domain":

C:\> nslookup builder.printerp.ai
Server:  hub.home.arpa
Address: 192.168.1.254

*** hub.home.arpa can't find builder.printerp.ai: Non-existent domain

This isn't a caching issue — customers have flushed DNS and rebooted their hubs repeatedly over several days with no change.

Here's the part that makes me think it's a filtering false positive:

Other hostnames in the exact same DNS zone resolve perfectly on the same BT connection, at the same moment, returning identical IP addresses:

api.printerp.ai            104.21.66.237, 172.67.165.220   -> resolves OK
builder.printerp.ai        104.21.66.237, 172.67.165.220   -> NXDOMAIN

Same nameservers, same IPs, same zone. Only that one hostname fails, and only on BT. If a customer sets their DNS to 8.8.8.8 it works instantly — so this is happening at BT's resolvers, not in our DNS config.

For what it's worth, the domain is clean everywhere I've checked:

Google Safe Browsing — "No unsafe content found"
Spamhaus — "no issues"
Netcraft — no fraud or malware indicators

We're a legitimate B2B business — the site is a tool UK print and apparel companies use to prepare artwork and manage print orders. We're BT Business customers ourselves.

I've emailed saferbrowsing@bt.com as well, but posting here in case a moderator can help move it along.

Is there anything else I can provide to get this looked at?

Thanks.

Re: BT DNS returns NXDOMAIN for our business domain - all BT customers affected, works on every o...

BethM — Wed, 02 Sep 2026 10:03:13 GMT

Hi briantruongau

Thanks for the information provided. For DNS and website categorisation concerns, the appropriate team is the Safe Browsing team via saferbrowsing@bt.com.

We appreciate you taking the time to report the issue and hope you're able to get a swift resolution from the team.

Re: BT DNS returns NXDOMAIN for our business domain - all BT customers affected, works on every othe

briantruongau — Wed, 02 Sep 2026 10:42:44 GMT

I sent an email to saferbrowsing@bt.com.
Many thanks.
Brian

topic Re: BT DNS returns NXDOMAIN for our business domain - all BT customers affected, works on every othe in Broadband

BT DNS returns NXDOMAIN for our business domain - all BT customers affected, works on every other IS

Re: BT DNS returns NXDOMAIN for our business domain - all BT customers affected, works on every o...

Re: BT DNS returns NXDOMAIN for our business domain - all BT customers affected, works on every othe