Apache2 Ubuntu not working, where to dig?

Question

Apache HTTP Server

Good afternoon!
I'm new to server administration, please help!
There is a VPS server with Ubuntu and a LAMP stack on it, the apache2 home page stopped opening by IP address, there is no domain.
PS I tried ~curl -X GET localhost, normally returns the page, what the hell?))
ISSUE CLOSED.
It looks like this is a problem of my provider, there is access from another provider.
Apparently this is due to the struggle with one messenger))

Answer 1

to the user from which the apache is started the rights to the folder /var/www/html are given?
Apache sigfaults you and cannot run the files in the folder, you see, read the log