Fatal error: Uncaught PDOException: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'NULL' for key 'sessions_user_id' in /www/wwwroot/sj.as-pub.com/public_web/lib/pkp/lib/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php:119 Stack trace: #0 /www/wwwroot/sj.as-pub.com/public_web/lib/pkp/lib/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php(119): PDOStatement->execute(NULL) #1 /www/wwwroot/sj.as-pub.com/public_web/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(489): Doctrine\DBAL\Driver\PDOStatement->execute() #2 /www/wwwroot/sj.as-pub.com/public_web/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(664): Illuminate\Database\Connection->Illuminate\Database\{closure}('INSERT INTO ses...', Array) #3 /www/wwwroot/sj.as-pub.com/public_web/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(631): Illuminate\Database\Connection->runQueryCallback('INSERT INTO ses...', Array, Object(Closure)) #4 /www/wwwroo in /www/wwwroot/sj.as-pub.com/public_web/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php on line 671