HMRC certificate expired? Companies House signature validation failed? Token not recognised on Windows 11? We diagnose and resolve UK digital signature, eIDAS and PKI errors live over a screen-shared remote call — usually in a single session.
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Government and enterprise signing platforms used across the UK.
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30 min
1 hour
Priority
No fix, no fee. You don't pay if we can't identify the root cause.
Representative British cases — Companies House, HMRC and Windows 11 token failures — with the root cause behind each one.
Accountancy practice · Manchester
Root cause: The PDF was signed to PAdES-B-B only: no timestamp, so the profile fell short of B-LT.
Signing profile switched to a timestamped PAdES-B-LT output and validated before resubmission.
Resolved in 40 minutes
NHS trust supplier · Leeds
Root cause: Legacy PKCS#11 middleware was no longer compatible with the updated CryptoAPI smart-card stack.
Current middleware installed, stale certificates cleared from the Personal store, token re-registered in Acrobat and Firefox.
Resolved in 1 session
Property solicitor · London
Root cause: The issuing TSP root sits on the UK Trust List but was not present in the local AATL cache.
Trust list refreshed and the anchor added, so counterparties see a valid signature.
Resolved in 30 minutes
Representative cases, anonymised for client confidentiality. Verified customer feedback is published through our Google Business Profile.
Since the UK left the EU, British qualified certificates are published on the UK Trust List maintained under UK eIDAS rather than the EU Trusted List. Practically, that means a certificate from a UK trust service provider — Sectigo, GlobalSign, Entrust, IdenTrust or a bank-issued credential — may validate perfectly in the UK and still show as untrusted for an EU counterparty whose validator only consults the EU list, and vice versa. Adobe Acrobat adds its own layer: it trusts the European Union Trusted Lists (EUTL) and the AATL, so a UK qualified certificate that has not been cross-listed produces the familiar amber 'validity is unknown' bar even though nothing is actually wrong with the signature.
The second common cause is the signature format. UK and EU workflows expect PAdES (PDF Advanced Electronic Signatures) with an embedded timestamp from a qualified time-stamping authority. A signature made without a timestamp validates today and fails in twelve months when the signing certificate expires, because there is no proof it was valid at the moment of signing.
Companies House web filing and the software filing gateway reject documents when the certificate chain cannot be built or the PDF was flattened after signing — the signature is still in the file but the byte range no longer matches. HMRC Government Gateway signing and Making Tax Digital submissions fail more often on browser and middleware issues than on the certificate itself. Land Registry and conveyancing panels apply their own rules, and many require a signature with an identity check that a basic electronic signature cannot satisfy under the Law Commission's 2019 guidance on electronic execution of documents.
UK GDPR and the Electronic Communications Act 2000 shape what evidence you need to retain, which is why we always leave you with a written validation report after a session — it is the artefact your compliance team or counterparty asks for.
British clients typically arrive with one of these on screen, usually an hour before a filing deadline.
AATL trust issues, Federal PKI credentials and smart-card middleware conflicts.
ConsignO certificate loading and federal GCKey signing problems.
eMudhra, Capricorn, ePass 2003 tokens on Income Tax, MCA21 and GST portals.
VANguard credentials, post-AUSkey migration and lodgement rejections.
Straight answers for Companies House, HMRC, eIDAS, DocuSign UK and Adobe Sign issues.
Adobe Acrobat only trusts certificates that chain to a root in its Approved Trust List (AATL) or the Windows Trust Store. Most UK qualified eIDAS certificates from providers like GlobalSign, Sectigo or Entrust need either an AATL update, manual trust anchoring, or an intermediate certificate installed. We identify the missing link and install the correct chain during the session.
Companies House validates against strict PAdES-B-LT profiles. The most common causes are: a missing timestamp (LTA), a broken chain because your intermediate CA cert is not embedded, or a signature made with SHA-1. We reconfigure your signing application (Adobe Acrobat, DocuSign, or your qualified signing service) to produce a compliant PAdES signature, and validate it against the Companies House checker before you re-submit.
Windows 11 24H2 changed the CryptoAPI Smart Card mini-drivers and often stops recognising older PKCS#11 middleware (SafeNet Authentication Client, Gemalto Classic Client, Feitian). We install the correct current driver, register the PKCS#11 module in Firefox/Adobe if needed, clear stale certificates from the Personal store, and re-enrol your token in one session.
Yes, but only when DocuSign is configured for "Sign with your own certificate" and the certificate is exposed via a compatible cloud signing service (e.g. Signicat, InfoCert, IDnow) or a local USB token. If DocuSign is throwing a certificate/eIDAS error, we bridge your qualified certificate into your DocuSign account and validate an end-to-end signing test.
Most UK signing failures are resolved in a single 30–60 minute Zoom session, and we usually have same-day slots between 09:00 and 19:00 UK time. Deadline-critical filings (Companies House, HMRC) are prioritised — book the Emergency Same-Day tier and mention your deadline.
You don't pay. Our "no fix, no fee" guarantee applies to every UK session: if we can't identify the root cause live, the session is free. When the fix requires action outside the call (e.g. a new qualified certificate from your trust service provider) you still receive a written remediation report your IT team can execute.
Same-day remote slots for HMRC, Companies House and DocuSign UK errors.
Next available slot typically within 1 business day
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