Q:

HTTP ERROR 500 Laravel on Digitalocean

I installed Laravel on Digitalocean vps (Ubuntu 16.04), but I have the following error, I have already given write permissions to storage.
This is the error

A:

I was using php 7.1.17 but I needed a higher version than php 7.1.3
Laravel 5.6 requirements:

PHP >= 7.1.3
OpenSSL PHP Extension
...

