It seems wordpress is outputting this ‘Service Unavailable’, but this site works fine before, and no files are modified.
I have searched code files with grep, only two places output ‘Service Unavailable’, but with different status code, any body can help?
wordpress output statuscode 200, content: service unavailable
Service Unavailableis usually a result of a mysql issue/warning. Try restarting the mysql service.Also, adding
define( 'WP_DEBUG', true );to yourwp-config.phpwill allow you to see the actual error message. https://codex.wordpress.org/WP_DEBUG