Solution:
You can use
function sm_restrict_admin_with_redirect() {
if( defined('DOING_AJAX') && DOING_AJAX ) {
//Allow ajax calls
return;
}
if( ! current_user_can( "manage_options" ) ) {
//Redirect to main page if the user has no "manage_options" capability
wp_redirect( get_site_url() );
exit;
}
}
add_action( 'admin_init', 'sm_restrict_admin_with_redirect', 1 );