Installation Plugins Failed and pluggable.php on line 1219

Hello,
I create a website and working fine but suddenly all plugins are deactivated. How? I don’t know.

I’m unsure as to what exactly caused this, but this was the error I got:

Warning: Cannot modify header information – headers already sent by (output started at /srv/users/serverpilot/apps/ahboopublishing/public/index.php:1) in /srv/users/serverpilot/apps/ahboopublishing/public/wp-includes/pluggable.php on line 1219

This account is business org.
Please Help me out this issue, as soon as possible.

The page I need help with: [log in to see the link]