Check this link: After installing magento 2.3 admin login page cant open properly
Find : /vendor/magento/framework/View/Element/Template/File/Validator.php:139find : foreach ($directories as $directory) { if (0 === strpos($realPath, $directory)) { return true; } } Replace with: foreach ($directories as $directory) { $realDirectory = $this->fileDriver->getRealPath($directory); // and replace `$directory` with `$realDirectory` if (0 === strpos($realPath, $realDirectory)) { return true; } }