register error and ticket make error

[Remco Official]

League\Flysystem\Exception: Impossible to create the root directory "../../whmcs/downloads". in /var/www/html/vendor/league/flysystem/src/Adapter/Local.php:106
Stack trace:
#0 /var/www/html/vendor/league/flysystem/src/Adapter/Local.php(78): League\Flysystem\Adapter\Local->ensureDirectory('../../whmcs/dow...')
#1 /var/www/html/vendor/whmcs/whmcs-foundation/lib/File/Provider/LocalStorageProvider.php(0): League\Flysystem\Adapter\Local->__construct('../../whmcs/dow...')
#2 /var/www/html/vendor/whmcs/whmcs-foundation/lib/File/Configuration/FileAssetSetting.php(0): WHMCS\File\Provider\LocalStorageProvider->createFilesystemAdapterForAssetType('email_template_...', '')
#3 /var/www/html/vendor/whmcs/whmcs-foundation/lib/File/Storage.php(0): WHMCS\File\Configuration\FileAssetSetting->createFilesystemAdapter('')
#4 /var/www/html/vendor/whmcs/whmcs-foundation/lib/File/Storage.php(0): WHMCS\File\Storage->createFilesystem('email_template_...')
#5 /var/www/html/vendor/illuminate/support/Facades/Facade.php(215): WHMCS\File\Storage->emailTemplateAttachments()
#6 /var/www/html/vendor/whmcs/whmcs-foundation/lib/Mail/Message.php(0): Illuminate\Support\Facades\Facade::__callStatic('emailTemplateAt...', Array)
#7 /var/www/html/vendor/whmcs/whmcs-foundation/lib/Mail/Emailer.php(0): WHMCS\Mail\Message::createFromTemplate(Object(WHMCS\Mail\Template))
#8 /var/www/html/includes/functions.php(0): WHMCS\Mail\Emailer::factoryByTemplate(Object(WHMCS\Mail\Template), 13, Array)
#9 /var/www/html/vendor/whmcs/whmcs-foundation/lib/User/Client.php(0): sendMessage('Client Email Ad...', 13, Array)
#10 /var/www/html/includes/clientfunctions.php(0): WHMCS\User\Client->sendEmailAddressVerification()
#11 /var/www/html/register.php(0): addClient('v', 'prive', '123', '1@1.nl', 'prive', '1213423', 'prive', 'Noord-Brabant', '111', 'NL', '+31.34323929353...', 'Poli#2004', '', '', true, Array, '4885b0ab-e944-4...', false, '')
#12 {main}

do shomwahn no how to fix