These all point to a handful of common causes, whether your exact error says "not found", "invalid", or "verification failed".
| If you see this | Try this |
|---|---|
| Browser can't detect the certificate at all | Confirm the token is connected, drivers are installed, and the token's management utility is running in the background. |
| "Certificate not found" | The system isn't seeing your token, try reconnecting it to a different USB port, and confirm the correct driver is installed. |
| Signature shows as "invalid" after signing | The certificate may have expired, been revoked, or the document may have been altered after signing, check certificate validity first. |
| "Verification failed" on a signed document | The recipient's system may not trust the issuing CA's root certificate, or the document was modified post-signing, neither is fixable by the signer after the fact. |
| "Failed to sign" during the signing process itself | Usually a middleware or driver issue rather than a certificate problem, confirm the correct portal-specific signing tool (emSigner, emBridge, PKI component) is running. |
1) Is the token physically detected? 2) Is the correct driver and portal middleware installed and running? 3) Is the certificate itself valid, not expired or revoked? 4) Are you registered on the specific portal you're using? Working through these in sequence resolves the large majority of "not detected / invalid / failed" issues.
We offer remote troubleshooting for these issues across any portal, and can issue a fresh DSC if yours has expired or is otherwise unusable.
This can happen if the recipient's system doesn't trust the issuing CA's root certificate chain, or if the document was altered after you signed it.
Typically "invalid" or a specific expiry-related message, depending on the software, either way, the fix is the same, renew the certificate.