diff --git a/acme/challenge.go b/acme/challenge.go
index e8870077..d65c262c 100644
--- a/acme/challenge.go
+++ b/acme/challenge.go
@@ -952,28 +952,28 @@ func doStepAttestationFormat(_ context.Context, prov Provisioner, ch *Challenge,
 	// Extract x5c and verify certificate
 	x5c, ok := att.AttStatement["x5c"].([]interface{})
 	if !ok {
-		return nil, NewError(ErrorBadAttestationStatementType, "x5c not present")
+		return nil, NewError(ErrorBadAttestationStatementType, "x5c not present").WithAdditionalErrorDetail()
 	}
 	if len(x5c) == 0 {
-		return nil, NewError(ErrorRejectedIdentifierType, "x5c is empty")
+		return nil, NewError(ErrorRejectedIdentifierType, "x5c is empty").WithAdditionalErrorDetail()
 	}
 	der, ok := x5c[0].([]byte)
 	if !ok {
-		return nil, NewError(ErrorBadAttestationStatementType, "x5c is malformed")
+		return nil, NewError(ErrorBadAttestationStatementType, "x5c is malformed").WithAdditionalErrorDetail()
 	}
 	leaf, err := x509.ParseCertificate(der)
 	if err != nil {
-		return nil, WrapError(ErrorBadAttestationStatementType, err, "x5c is malformed")
+		return nil, WrapError(ErrorBadAttestationStatementType, err, "x5c is malformed").WithAdditionalErrorDetail()
 	}
 	intermediates := x509.NewCertPool()
 	for _, v := range x5c[1:] {
 		der, ok = v.([]byte)
 		if !ok {
-			return nil, NewError(ErrorBadAttestationStatementType, "x5c is malformed")
+			return nil, NewError(ErrorBadAttestationStatementType, "x5c is malformed").WithAdditionalErrorDetail()
 		}
 		cert, err := x509.ParseCertificate(der)
 		if err != nil {
-			return nil, WrapError(ErrorBadAttestationStatementType, err, "x5c is malformed")
+			return nil, WrapError(ErrorBadAttestationStatementType, err, "x5c is malformed").WithAdditionalErrorDetail()
 		}
 		intermediates.AddCert(cert)
 	}
@@ -983,7 +983,7 @@ func doStepAttestationFormat(_ context.Context, prov Provisioner, ch *Challenge,
 		CurrentTime:   time.Now().Truncate(time.Second),
 		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
 	}); err != nil {
-		return nil, WrapError(ErrorBadAttestationStatementType, err, "x5c is not valid")
+		return nil, WrapError(ErrorBadAttestationStatementType, err, "x5c is not valid").WithAdditionalErrorDetail()
 	}
 
 	// Verify proof of possession of private key validating the key
@@ -993,10 +993,10 @@ func doStepAttestationFormat(_ context.Context, prov Provisioner, ch *Challenge,
 	var sig []byte
 	csig, ok := att.AttStatement["sig"].([]byte)
 	if !ok {
-		return nil, NewError(ErrorBadAttestationStatementType, "sig not present")
+		return nil, NewError(ErrorBadAttestationStatementType, "sig not present").WithAdditionalErrorDetail()
 	}
 	if err := cbor.Unmarshal(csig, &sig); err != nil {
-		return nil, NewError(ErrorBadAttestationStatementType, "sig is malformed")
+		return nil, NewError(ErrorBadAttestationStatementType, "sig is malformed").WithAdditionalErrorDetail()
 	}
 	keyAuth, err := KeyAuthorization(ch.Token, jwk)
 	if err != nil {
@@ -1006,23 +1006,23 @@ func doStepAttestationFormat(_ context.Context, prov Provisioner, ch *Challenge,
 	switch pub := leaf.PublicKey.(type) {
 	case *ecdsa.PublicKey:
 		if pub.Curve != elliptic.P256() {
-			return nil, WrapError(ErrorBadAttestationStatementType, err, "unsupported elliptic curve %s", pub.Curve)
+			return nil, WrapError(ErrorBadAttestationStatementType, err, "unsupported elliptic curve %s", pub.Curve).WithAdditionalErrorDetail()
 		}
 		sum := sha256.Sum256([]byte(keyAuth))
 		if !ecdsa.VerifyASN1(pub, sum[:], sig) {
-			return nil, NewError(ErrorBadAttestationStatementType, "failed to validate signature")
+			return nil, NewError(ErrorBadAttestationStatementType, "failed to validate signature").WithAdditionalErrorDetail()
 		}
 	case *rsa.PublicKey:
 		sum := sha256.Sum256([]byte(keyAuth))
 		if err := rsa.VerifyPKCS1v15(pub, crypto.SHA256, sum[:], sig); err != nil {
-			return nil, NewError(ErrorBadAttestationStatementType, "failed to validate signature")
+			return nil, NewError(ErrorBadAttestationStatementType, "failed to validate signature").WithAdditionalErrorDetail()
 		}
 	case ed25519.PublicKey:
 		if !ed25519.Verify(pub, []byte(keyAuth), sig) {
-			return nil, NewError(ErrorBadAttestationStatementType, "failed to validate signature")
+			return nil, NewError(ErrorBadAttestationStatementType, "failed to validate signature").WithAdditionalErrorDetail()
 		}
 	default:
-		return nil, NewError(ErrorBadAttestationStatementType, "unsupported public key type %T", pub)
+		return nil, NewError(ErrorBadAttestationStatementType, "unsupported public key type %T", pub).WithAdditionalErrorDetail()
 	}
 
 	// Parse attestation data:
diff --git a/acme/challenge_test.go b/acme/challenge_test.go
index 1f5135ca..e489aac7 100644
--- a/acme/challenge_test.go
+++ b/acme/challenge_test.go
@@ -3703,7 +3703,7 @@ func Test_deviceAttest01Validate(t *testing.T) {
 							assert.Equal(t, ChallengeType("device-attest-01"), updch.Type)
 							assert.Equal(t, "12345678", updch.Value)
 
-							err := NewError(ErrorBadAttestationStatementType, "x5c not present")
+							err := NewError(ErrorBadAttestationStatementType, "x5c not present").WithAdditionalErrorDetail()
 
 							assert.EqualError(t, updch.Error.Err, err.Err.Error())
 							assert.Equal(t, err.Type, updch.Error.Type)
diff --git a/acme/errors.go b/acme/errors.go
index 59bd2e11..06b45114 100644
--- a/acme/errors.go
+++ b/acme/errors.go
@@ -310,8 +310,8 @@ func (e *Error) AddSubproblems(subproblems ...Subproblem) *Error {
 // more information to the ACME client.
 func (e *Error) WithAdditionalErrorDetail() *Error {
 	// prevent internal server errors from disclosing
-	// the internal error to the client.
-	if e.Status >= 500 {
+	// the internal error to the client at all times.
+	if e == nil || e.Status >= 500 {
 		return e
 	}