diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6b82845c8..ade0c245b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,13 +8,21 @@ on:
 
 jobs:
   tests:
-    runs-on: ubuntu-latest
-
     strategy:
       fail-fast: false
       matrix:
-        php: [8.0, 8.1, 8.2]
+        php: [8.1, 8.2]
+        os: [ubuntu-22.04]
         stability: [prefer-lowest, prefer-stable]
+        include:
+          - os: ubuntu-20.04
+            php: 8.0
+            stability: prefer-lowest
+          - os: ubuntu-20.04
+            php: 8.0
+            stability: prefer-stable
+
+    runs-on: ${{ matrix.os }}
 
     name: PHP ${{ matrix.php }} - ${{ matrix.stability }}
 
diff --git a/composer.json b/composer.json
index 94e89de99..613784833 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,6 @@
         "lcobucci/jwt": "^4.3 || ^5.0",
         "psr/http-message": "^1.0.1 || ^2.0",
         "defuse/php-encryption": "^2.3",
-        "ext-json": "*",
         "lcobucci/clock": "^2.2 || ^3.0"
     },
     "require-dev": {
diff --git a/src/AuthorizationValidators/BearerTokenValidator.php b/src/AuthorizationValidators/BearerTokenValidator.php
index c817d53b1..5da9ba8c6 100644
--- a/src/AuthorizationValidators/BearerTokenValidator.php
+++ b/src/AuthorizationValidators/BearerTokenValidator.php
@@ -113,7 +113,7 @@ public function validateAuthorization(ServerRequestInterface $request)
             $constraints = $this->jwtConfiguration->validationConstraints();
             $this->jwtConfiguration->validator()->assert($token, ...$constraints);
         } catch (RequiredConstraintsViolated $exception) {
-            throw OAuthServerException::accessDenied('Access token could not be verified');
+            throw OAuthServerException::accessDenied('Access token could not be verified', null, $exception);
         }
 
         $claims = $token->claims();
diff --git a/tests/Utils/CryptKeyTest.php b/tests/Utils/CryptKeyTest.php
index 7190864c6..b9c53b660 100644
--- a/tests/Utils/CryptKeyTest.php
+++ b/tests/Utils/CryptKeyTest.php
@@ -54,9 +54,6 @@ public function testKeyString()
 
     public function testUnsupportedKeyType()
     {
-        if (\str_starts_with(\phpversion(), '8.0')) {
-            $this->markTestSkipped('Cannot generate key on PHP 8.0 runner. Investigating');
-        }
         $this->expectException(\LogicException::class);
         $this->expectExceptionMessage('Unable to read key');