Installing grav, HTTP 500 Error

It’s been hours… I am trying to install Grav but I always get the HTTP Interal Server Error (500)
and my head is gonna blow soon.

I have tried everything from here: https://learn.getgrav.org/16/troubleshooting/internal-server-error

What else can I do, please help me.

FOUND THIS ERROR IN THE APACHE LOG
[Sun Jun 23 14:03:34.662104 2019] [php7:error] [pid 4487] [client 188.123.100.151:44511] PHP Fatal error: Uncaught RuntimeException: Creating directory failed for /var/www/cms/cache/compiled/files/d10d8195eebb120aa2a0782d81d13f32.yaml.php in /var/www/cms/vendor/rockettheme/toolbox/File/src/File.php:325\nStack trace:\n#0 /var/www/cms/vendor/rockettheme/toolbox/File/src/PhpFile.php(31): RocketTheme\Toolbox\File\File->save(Array)\n#1 /var/www/cms/system/src/Grav/Common/File/CompiledFile.php(65): RocketTheme\Toolbox\File\PhpFile->save(Array)\n#2 /var/www/cms/system/src/Grav/Common/Config/Setup.php(215): Grav\Common\File\CompiledYamlFile->content()\n#3 /var/www/cms/system/src/Grav/Common/Service/ConfigServiceProvider.php(30): Grav\Common\Config\Setup->init()\n#4 /var/www/cms/vendor/pimple/pimple/src/Pimple/Container.php(118): Grav\Common\Service\ConfigServiceProvider->Grav\Common\Service\{closure}(Object(Grav\Common\Grav))\n#5 /var/www/cms/system/src/Grav/Common/Grav.php(166): Pimple\Container->offsetGet(‘setup’)\n#6 /var/www/cms/system/src/Grav/Common/Grav.php(449): Grav\Common\Grav->Grav\Common\{closure}()\n#7 /var/www/cms/s in /var/www/cms/system/src/Grav/Common/File/CompiledFile.php on line 81