webmaster 404 error and fb open graph error

so beside that i cant edit the .htaccess unless i deactivate better wp security, there r 2 problems:
1) however i installed facebook open graph and deactivated the meta option i get these errors:
URL returned a bad HTTP response code.
The ‘og:url’ property should be explicitly provided, even if a value can be inferred from other tags.
Inferred Property: The ‘og:title’ property should be explicitly provided, even if a value can be inferred from other tags.

2) google webmaster gives me that sitemap error even that i deleted them from the log and keeping my plugins number to minimum
General HTTP error: 404 not found
HTTP Error: 404

im desperate 4 help! thanks

https://www.ads-software.com/extend/plugins/better-wp-security/