500 Internal Server

Hi,

I bought a new domain for this. It's a .co, not sure if that matters.
I made my FTP account, got FileZilla, followed the instructions for Grawlix, did everything, and I get 500 Internal Server Error.
I've been trying to fix this for hours. I even opened the file in Notepad ++, resaved it. Then put in the "#" before the php_flag line, and still nothing.
Is it my domain .co? My hosting service?

Please help.

I didn't find the right solution from the Internet.

References:-
https://bit.ly/2v9OBGQ
Marketing video company

Thanks