Fatal error: Uncaught CodeIgniter\Cache\Exceptions\CacheException: Cache unable to write to "/opt/lampp/htdocs/exam_beta/writable/cache/". in /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Cache/Handlers/FileHandler.php:66 Stack trace: #0 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Cache/Handlers/FileHandler.php(66): CodeIgniter\Cache\Exceptions\CacheException::forUnableToWrite('/opt/lampp/htdo...') #1 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Cache/CacheFactory.php(65): CodeIgniter\Cache\Handlers\FileHandler->__construct(Object(Config\Cache)) #2 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/Services.php(125): CodeIgniter\Cache\CacheFactory::getHandler(Object(Config\Cache)) #3 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(258): CodeIgniter\Config\Services::cache(Object(Config\Cache), false) #4 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(199): CodeIgniter\Config\BaseService::__callStatic('cache', Array) #5 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/Services.php(120): CodeIgniter\Config\BaseService::getSharedInstance('cache', NULL) #6 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(258): CodeIgniter\Config\Services::cache() #7 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/Services.php(450): CodeIgniter\Config\BaseService::__callStatic('cache', Array) #8 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(258): CodeIgniter\Config\Services::responsecache(Object(Config\Cache), NULL, false) #9 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(199): CodeIgniter\Config\BaseService::__callStatic('responsecache', Array) #10 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/Services.php(446): CodeIgniter\Config\BaseService::getSharedInstance('responsecache', NULL, NULL) #11 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(258): CodeIgniter\Config\Services::responsecache() #12 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/CodeIgniter.php(196): CodeIgniter\Config\BaseService::__callStatic('responsecache', Array) #13 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/Services.php(160): CodeIgniter\CodeIgniter->__construct(Object(Config\App)) #14 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(258): CodeIgniter\Config\Services::codeigniter(Object(Config\App), false) #15 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(199): CodeIgniter\Config\BaseService::__callStatic('codeigniter', Array) #16 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/Services.php(155): CodeIgniter\Config\BaseService::getSharedInstance('codeigniter', NULL) #17 /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Config/BaseService.php(258): CodeIgniter\Config\Services::codeigniter() #18 /opt/lampp/htdocs/exam_beta/index.php(68): CodeIgniter\Config\BaseService::__callStatic('codeigniter', Array) #19 {main} thrown in /opt/lampp/htdocs/exam_beta/vendor/codeigniter4/framework/system/Cache/Handlers/FileHandler.php on line 66