EventReporter Event ID 11055: TLS client certificate fingerprint could not be computed#

Answer#

The listener is configured for certificate-fingerprint authentication and could not compute the required SHA-1 digest from the verified client certificate. It rejects the connection before comparing the certificate with permitted fingerprints.

Event details#

Event ID: 11055
Severity: Warning
Component: TLS peer authorization
Windows Event Log source: Adiscon EvntSLog
Available since: 26.07
Message pattern: TLS client certificate fingerprint could not be computed. Additional detail: {event_detail}

Possible causes#

The presented certificate has an unexpected or unsupported encoding that prevents fingerprint calculation.
The cryptographic provider could not perform the digest operation, or a resource or library error occurred after certificate verification.

Immediate checks#

Preserve the complete event and bounded debug log and identify the exact client certificate used for the rejected handshake.
Use certutil to dump and verify the certificate and reproduce the failure once with the same client and listener.
Replace the client certificate only if validation fails; if a valid certificate still triggers this event, collect the listed evidence and escalate without weakening peer authentication.

Detailed procedures#

Resolve a destination and test its TCP port — Verify DNS, selected address, routing, and TCP establishment.
Verify TLS certificates, private keys, and permitted peers — Identify CA, certificate, private-key, trust-chain, and permitted-peer failures without exposing private key material.
Collect an Event ID and neighboring product events — Preserve the complete event and the product events immediately before and after it.
Export configuration and collect a bounded debug log — Create a text configuration export and time-bounded debug capture, then disable debugging.

Verify the result#

Confirm that the listener computes and matches the authorized fingerprint, accepts one TLS test session, delivers its message, and no longer emits Event ID 11055.

Evidence to collect#

The complete Windows Application Event Log entry, including all event detail.
The product version, listener name, TLS mode, timestamp with time zone, OpenSSL detail, and sanitized permitted-fingerprint format.
Certutil output and sanitized certificate subject, issuer, serial number, validity dates, and calculated fingerprints plus a bounded debug log; omit private keys.

Escalation#

If the event continues after the detailed procedures, collect the listed evidence and contact Adiscon Support.