diff --git a/CHANGELOG.md b/CHANGELOG.md
index bc2cc8b..e88aa6d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- `OpenIdLoginAuthenticator::validateClaims()` no longer collapses library
+  exceptions into a generic `ValidationException`. Specific subtypes
+  (`HttpException`, `CodeException`, `ClaimsException`, `JsonException`,
+  `CacheException`, etc.) bubble up unchanged so callers can react to the
+  actual failure mode (e.g., timeout vs. nonce mismatch). All subtypes
+  already extend `ItkOpenIdConnectException`, which the method's `@throws`
+  declaration already covered, so any caller catching the parent keeps
+  working.
+- `OpenIdLoginAuthenticator::onAuthenticationFailure()` now chains the
+  original exception via `previous` and includes its message, so logs and
+  error reporters retain the cause. Symfony's security still renders only
+  the safe message key to the user.
 - Bumped actions/checkout from v5 to v6 in all GitHub workflows
 - Renamed PHP_EXEC variable to PHP in Taskfile
 - Added lint:composer task to Taskfile
diff --git a/src/Security/OpenIdLoginAuthenticator.php b/src/Security/OpenIdLoginAuthenticator.php
index 2379900..be11103 100644
--- a/src/Security/OpenIdLoginAuthenticator.php
+++ b/src/Security/OpenIdLoginAuthenticator.php
@@ -60,21 +60,19 @@ protected function validateClaims(Request $request): array
             throw new ValidationException('Nonce empty or not found');
         }
 
-        try {
-            $code = $request->query->get('code');
+        $code = $request->query->get('code');
 
-            if (!is_string($code)) {
-                throw new ValidationException('Missing or invalid code');
-            }
-
-            $idToken = $provider->getIdToken($code);
-            $claims = $provider->validateIdToken($idToken, $oauth2nonce);
-            // Authentication successful
-        } catch (ItkOpenIdConnectException $exception) {
-            // Handle failed authentication
-            throw new ValidationException($exception->getMessage());
+        if (!is_string($code)) {
+            throw new ValidationException('Missing or invalid code');
         }
 
+        // Library exceptions (HttpException, CodeException, ClaimsException,
+        // ValidationException, JsonException, CacheException, KeyException,
+        // DecodeException) all extend ItkOpenIdConnectException and bubble up
+        // unchanged so callers can react to specific failure modes.
+        $idToken = $provider->getIdToken($code);
+        $claims = $provider->validateIdToken($idToken, $oauth2nonce);
+
         /** @var array<string, string> $claimsArray */
         $claimsArray = (array) $claims;
 
@@ -83,6 +81,9 @@ protected function validateClaims(Request $request): array
 
     public function onAuthenticationFailure(Request $request, AuthenticationException $exception): ?Response
     {
-        throw new AuthenticationException('Error occurred validating openid login');
+        // Preserve the cause so logs and error reporters can see what actually
+        // failed (timeout, signature mismatch, wrong nonce, etc.). Symfony's
+        // security renders only the safe message key to the user.
+        throw new AuthenticationException(sprintf('Error occurred validating openid login: %s', $exception->getMessage()), $exception->getCode(), $exception);
     }
 }
diff --git a/tests/Security/OpenIdLoginAuthenticatorTest.php b/tests/Security/OpenIdLoginAuthenticatorTest.php
index 238b468..2bd6161 100644
--- a/tests/Security/OpenIdLoginAuthenticatorTest.php
+++ b/tests/Security/OpenIdLoginAuthenticatorTest.php
@@ -3,6 +3,7 @@
 namespace ItkDev\OpenIdConnectBundle\Tests\Security;
 
 use ItkDev\OpenIdConnect\Exception\ClaimsException;
+use ItkDev\OpenIdConnect\Exception\HttpException;
 use ItkDev\OpenIdConnect\Exception\ValidationException;
 use ItkDev\OpenIdConnect\Security\OpenIdConfigurationProvider;
 use ItkDev\OpenIdConnectBundle\Security\OpenIdConfigurationProviderManager;
@@ -39,14 +40,18 @@ public function testSupports(): void
         $this->assertTrue($this->authenticator->supports($request));
     }
 
-    public function testOnAuthenticationFailure(): void
+    public function testOnAuthenticationFailurePreservesCause(): void
     {
-        $this->expectException(AuthenticationException::class);
-
+        $causeMessage = 'Original cause message';
         $stubRequest = $this->createStub(Request::class);
-        $exception = new AuthenticationException();
-
-        $this->authenticator->onAuthenticationFailure($stubRequest, $exception);
+        $cause = new AuthenticationException($causeMessage);
+
+        try {
+            $this->authenticator->onAuthenticationFailure($stubRequest, $cause);
+        } catch (AuthenticationException $thrown) {
+            $this->assertSame($cause, $thrown->getPrevious(), 'Original exception must be chained as previous');
+            $this->assertStringContainsString($causeMessage, $thrown->getMessage(), 'Cause message must be preserved for logs');
+        }
     }
 
     public function testValidateClaimsWrongState(): void
@@ -85,10 +90,11 @@ public function testValidateClaimsMissingCode(): void
         $this->authenticator->authenticate($request);
     }
 
-    public function testValidateClaimsCodeDoesNotValidate(): void
+    public function testValidateClaimsBubblesClaimsExceptionUnchanged(): void
     {
+        $claimsMessage = 'ID token has incorrect nonce';
         $stubProvider = $this->createStub(OpenIdConfigurationProvider::class);
-        $stubProvider->method('validateIdToken')->willThrowException(new ClaimsException('test message'));
+        $stubProvider->method('validateIdToken')->willThrowException(new ClaimsException($claimsMessage));
         $this->stubProviderManager->method('getProvider')->willReturn($stubProvider);
 
         $request = $this->createStub(Request::class);
@@ -96,8 +102,28 @@ public function testValidateClaimsCodeDoesNotValidate(): void
 
         $this->setupStubSessionOnRequest($request);
 
-        $this->expectException(ValidationException::class);
-        $this->expectExceptionMessage('test message');
+        // ClaimsException must reach the caller as itself, not collapsed into the
+        // base ItkOpenIdConnectException or ValidationException, so consumers can
+        // distinguish a bad nonce/issuer/audience from a network failure.
+        $this->expectException(ClaimsException::class);
+        $this->expectExceptionMessage($claimsMessage);
+        $this->authenticator->authenticate($request);
+    }
+
+    public function testValidateClaimsBubblesHttpExceptionUnchanged(): void
+    {
+        $httpMessage = 'Connection timed out';
+        $stubProvider = $this->createStub(OpenIdConfigurationProvider::class);
+        $stubProvider->method('getIdToken')->willThrowException(new HttpException($httpMessage));
+        $this->stubProviderManager->method('getProvider')->willReturn($stubProvider);
+
+        $request = $this->createStub(Request::class);
+        $request->query = new InputBag(['state' => 'test_state', 'code' => 'test_code']);
+
+        $this->setupStubSessionOnRequest($request);
+
+        $this->expectException(HttpException::class);
+        $this->expectExceptionMessage($httpMessage);
         $this->authenticator->authenticate($request);
     }