2、wordpress主题和版本程序不兼容问题，通过ftp传送php文件到电脑本地用dreamweaver等编辑软件修改保存后，再上传。

wordpress4.9.4后台修改php文件(添加或删除代码)时出现“未能与站点联系来检查致命错误，”主要以下原因：

1、你添加的wordpress代码语法错误或代码冲突

WordPress 4.9 版本后台编辑主题PHP文件无法保存解决方法

1、打开wp-admin/includes/file.php文件，

3、加拿大PC28网站入口目前wordpress简体中文版最新为WordPress 4.9.4。删除492-599行如下代码：

if ( $is_active && 'php' === $extension ) {		$scrape_key = md5( rand() );		$transient = 'scrape_key_' . $scrape_key;		$scrape_nonce = strval( rand() );		set_transient( $transient, $scrape_nonce, 60 ); // It shouldn't take more than 60 seconds to make the two loopback requests.		$cookies = wp_unslash( $_COOKIE );		$scrape_params = array(			'wp_scrape_key' => $scrape_key,			'wp_scrape_nonce' => $scrape_nonce,		);		$headers = array(			'Cache-Control' => 'no-cache',		);		// Include Basic auth in loopback requests.		if ( isset( $_SERVER['PHP_AUTH_USER'] ) && isset( $_SERVER['PHP_AUTH_PW'] ) ) {			$headers['Authorization'] = 'Basic ' . base64_encode( wp_unslash( $_SERVER['PHP_AUTH_USER'] ) . ':' . wp_unslash( $_SERVER['PHP_AUTH_PW'] ) );		}		// Make sure PHP process doesn't die before loopback requests complete.		@set_time_limit( 300 );		// Time to wait for loopback requests to finish.		$timeout = 100;		$needle_start = "###### wp_scraping_result_start:$scrape_key ######";		$needle_end = "###### wp_scraping_result_end:$scrape_key ######";		// Attempt loopback request to editor to see if user just whitescreened themselves.		if ( $plugin ) {			$url = add_query_arg( compact( 'plugin', 'file' ), admin_url( 'plugin-editor.php' ) );		} elseif ( isset( $stylesheet ) ) {			$url = add_query_arg(				array(					'theme' => $stylesheet,					'file' => $file,				),				admin_url( 'theme-editor.php' )			);		} else {			$url = admin_url();		}		$url = add_query_arg( $scrape_params, $url );		$r = wp_remote_get( $url, compact( 'cookies', 'headers', 'timeout' ) );		$body = wp_remote_retrieve_body( $r );		$scrape_result_position = strpos( $body, $needle_start );		$loopback_request_failure = array(			'code' => 'loopback_request_failed',			'message' => __( 'Unable to communicate back with site to check for fatal errors, so the PHP change was reverted. You will need to upload your PHP file change by some other means, such as by using SFTP.' ),		);		$json_parse_failure = array(			'code' => 'json_parse_error',		);		$result = null;		if ( false === $scrape_result_position ) {			$result = $loopback_request_failure;		} else {			$error_output = substr( $body, $scrape_result_position + strlen( $needle_start ) );			$error_output = substr( $error_output, 0, strpos( $error_output, $needle_end ) );			$result = json_decode( trim( $error_output ), true );			if ( empty( $result ) ) {				$result = $json_parse_failure;			}		}		// Try making request to homepage as well to see if visitors have been whitescreened.		if ( true === $result ) {			$url = home_url( '/' );			$url = add_query_arg( $scrape_params, $url );			$r = wp_remote_get( $url, compact( 'cookies', 'headers', 'timeout' ) );			$body = wp_remote_retrieve_body( $r );			$scrape_result_position = strpos( $body, $needle_start );			if ( false === $scrape_result_position ) {				$result = $loopback_request_failure;			} else {				$error_output = substr( $body, $scrape_result_position + strlen( $needle_start ) );				$error_output = substr( $error_output, 0, strpos( $error_output, $needle_end ) );				$result = json_decode( trim( $error_output ), true );				if ( empty( $result ) ) {					$result = $json_parse_failure;				}			}		}		delete_transient( $transient );		if ( true !== $result ) {			// Roll-back file change.			file_put_contents( $real_file, $previous_content );			if ( function_exists( 'opcache_invalidate' ) ) {				opcache_invalidate( $real_file, true );			}			if ( ! isset( $result['message'] ) ) {				$message = __( 'An unidentified error has occurred.' );			} else {				$message = $result['message'];				unset( $result['message'] );			}			return new WP_Error( 'php_error', $message, $result );		}	}

这个方法仅仅是WordPress官方出更新前的一个临时替代方式，

3、

2、