503 service unavailable - Apache/2.4.18 (Ubuntu) Server at Port 80

I am totally new to Ubuntu, Linux, Apache and terminals.. so really hoping if someone could guide me to resolve this issue:

"503 service unavailable - The server is temporarily unable to service your request due... Apache/2.4.18 (Ubuntu) Server at Port 80"

This was caused when I did a system reboot in Ubuntu (via SSH - putty). The reason I did a reebot is because it showed on the system "Required System Reboot" - '108 packahes can be updates'

Googled how to reboot and did $ Sudo Reboot

After reboot my website went down and I am unable to get it up again. Have no clue what happened there.

I am also getting this line in the terminal/Putty '-bash: /home/ubuntu/.rvm/scripts/rvm: No such file or directory'

Please please can someone guide me here. Would be realy great help. I have no dev/Ubuntu experience. I am like totally stuck :(

Thanks, Swaps