[HvG Community]

The solution was re-installing.


Also, make sure that when you are setting permissions on folders, owner and group are the same as your web server user.

So if you are using apache, your web server user is probably www-data.

What you can also do is add your personal account to www-data group:
sudo adduser username www-data
And then also add write access to group. So instead of sudo chmod -R 644 demos you will do 664.

And also don't have newest version of PHP like me (7.4), else you will have to go around dozen of files and remove code that is incompatible.