Sub-domain Server 500 error?

Hi All,

Feel like a beautiful idiot now… Allow me to bullet point the steps I followed and maybe you can see where I missed something or did not do something.

1- Created a sub-domain (in cpanel)
2- created a data base with new user (in cpanel)
3- Downloaded wordpress 4.3.1
4- Changed the name from wp-config-sample.php to wp-config.php
5- inside the wp-config I changed the database name, username & password
6- loaded the api salt URL and copied and pasted my new salt keys to the relevant area inside wp-config
7- saved!!
8- uploaded wp to the subdomains folder in the main domains root via ftp
9- typed https://subdomain.maindonain.xyz/wp-login.php
10- filled UN & PW hit enter
11- Then it goes to https://subdomain.maindonain.xyz.xyz/wp-admin/

with Server error 500

Will appreciate any help!!

Beven