Fatal error: Uncaught Error: Class 'Drupal\Core\Block\BlockBase' not found in /var/www/html/tmp/contrib/openid_connect/src/Plugin/Block/OpenIDConnectLoginBlock.php:21 Stack trace: #0 {main} thrown in /var/www/html/tmp/contrib/openid_connect/src/Plugin/Block/OpenIDConnectLoginBlock.php on line 21