问尝试将W3总缓存设置为与Cloudfront一起工作的CDN。为什么我会犯这个严重的错误？

EN

2018-11-22T01:10:19+00:00 CRITICAL Uncaught Error: Class 'DOMDocument' not found in /var/www/html/wp-content/plugins/w3-total-cache/lib/S3.php:1770
Stack trace:
#0 /var/www/html/wp-content/plugins/w3-total-cache/lib/S3.php(1403): S3::getCloudFrontDistributionConfigXML('myurl.com.a...', 'custom', true, '', '154234534.333'(I changed this number just in case.), Array, NULL, NULL, Array)
#1 /var/www/html/wp-content/plugins/w3-total-cache/CdnEngine_S3_Cf.php(363): S3::createDistribution(',myurl.com.a...', 'custom', true, Array)
#2 /var/www/html/wp-content/plugins/w3-total-cache/Cdn_AdminActions.php(471): W3TC\CdnEngine_S3_Cf->create_container('', 'Incorrect type.')
#3 /var/www/html/wp-content/plugins/w3-total-cache/Root_AdminActions.php(25): W3TC\Cdn_AdminActions->w3tc_cdn_create_container()
#4 /var/www/html/wp-content/plugins/w3-total-cache/Generic_Plugin_Admin.php(159): W3TC\Root_AdminActions->execute('w3tc_cdn_create...')
#5 /var/www/html/wp-includes/class-wp-hook.php(286): W3TC\Generic_Plugin_Admin->load('')
#6 /var/www/html/wp-includes/class-wp-hook.php(310): WP_Hook->app in /var/www/html/wp-content/plugins/w3-total-cache/lib/S3.php on line 1770