weird wp-config changes and main site "The Multi-Domains plugin is only compatible with WordPre

Hope any staff with same time zone.

I got problem looks like since yesterday but just realize a couple minutes ago that I can not access to my main site. If enter the url goes to http://current_domain_ (forget)

I can not go to admin area, the subsites looks OK. LAst action was updated domain mapping and install wp on same server hosting but non-multisite type.
My wp-config file changed that no wp_allow_multisite - true .. weird heh .. then I add that wp_allow_blabla ...
Then I enter my url and now changes to white screen with "The Multi-Domains plugin is only compatible with WordPress Multisite." text on it.
Please advice ....