This topic

Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8.8.8

BeckySmith — Tue, 23 Jun 2026 09:33:33 GMT

Hi all,

Looking for help escalating a DNS issue affecting sepsistrust.tfaforms.net (a donation/event registration form for The UK Sepsis Trust charity, hosted via FormAssembly).

For over two weeks, this domain has failed to resolve for BT broadband customers — including members of the public trying to donate, not just our own office connection.

Evidence:

Via BT's own DNS:

nslookup sepsistrust.tfaforms.netServer: bthub.home*** bthub.home can't find sepsistrust.tfaforms.net: Non-existent domain

Via Google DNS:

nslookup sepsistrust.tfaforms.net 8.8.8.8Non-authoritative answer:Name: sepsistrust.eu2.formassembly.appAddresses: 13.135.174.191, 13.135.243.243Aliases: sepsistrust.tfaforms.net

Via Cloudflare DNS (1.1.1.1): identical result to Google — resolves fine.

I've checked both IPs (13.135.174.191 / 13.135.243.243) against Spamhaus, multirbl.valli.pl, and VirusTotal — all completely clean, no blocklist entries anywhere.

So this is resolving correctly via two independent major public resolvers but failing specifically and consistently on BT's own DNS infrastructure, despite a clean reputation everywhere else. I've already emailed categorisation@bt.com with the same evidence, but given the impact on a charity's public donation forms, I wanted to also raise it here in case a staff member or Superuser can help get it escalated to the DNS/filtering team directly.

Happy to provide any further diagnostics. Thanks in advance for any help.

Re: Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8

BeckySmith — Tue, 23 Jun 2026 11:06:34 GMT

@Steve_M I've been trawling the forum looking for similar issues and I wonder if this is something you'd be able to help with?

I'd be so grateful! If you could even give me a clue about who to contact or escalate this to.

UK Sepsis Trust is a charity working to prevent deaths from sepsis and we use web forms for all our supporter interactions - at the moment these are inaccessible to anyone using BT broadband so it's a big problem for us.

Thanks very much

Re: Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8

gg30340 — Tue, 23 Jun 2026 11:25:02 GMT

I am a BT broadband customer and if it helps I have tried the address you posted... sepsistrust.tfaforms.net and it takes me to the following page:-

FormAssembly: Essentials | UK Sepsis Trust : Users

Re: Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8

BeckySmith — Tue, 23 Jun 2026 11:27:49 GMT

Thanks so much for replying. I'm honestly not sure what to do, several of the users who aren't able to load this domain (or see the forms via our website) are BT customers, so I thought this was the common factor.

Re: Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8

Steve_M — Tue, 23 Jun 2026 12:45:04 GMT

Hi @BeckySmith ,

I've raised this with the people who can fix it so give them a few minutes.

Steve

Re: Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8

BeckySmith — Tue, 23 Jun 2026 13:35:19 GMT

OMG you're a life saver.

Re: Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8

Steve_M — Tue, 23 Jun 2026 13:38:22 GMT

Looks to be back in service now 🙂

Steve

Re: Domain returning NXDOMAIN on BT DNS only — clean on all blocklists, resolves fine on 1.1.1.1/8.8

BeckySmith — Tue, 23 Jun 2026 13:56:52 GMT

You have no idea how relieved I am. Thank you so much!