Wordpress LScache Plugin: Uncaught Error: Class LiteSpeedLibHTML_MIN not found
Last Updated on: Wed, 15 Apr 2026 00:00:02 Hi, We have two post types called events and courses on our website. 500 server errors appear on single pages of these post types. Actually the pages open but the 500 error appears in the browser console. I created the following reports using the log tools of the Litespeed plugin. This error only appears for visitors who are not logged in. Such an error does not occur on the same pages in people who are logged in. Additionally, when I completely disabled the cache on these pages, the problem was resolved for 1 day. But today the same problem appears again. Screenshot: https://prnt.sc/JQYD_YW8yeMm /27/22 12:13:37.642 [46.197.24.97:27736 1 SMU] [Media] webp replacing: https://###################/wp-content/uploads/2022/06/###################.png 10/27/22 12:13:37.643 [46.197.24.97:27736 1 SMU] [Media] - replaced to: https://###################/wp-content/uploads/2022/06/###################.png.webp 10/27/22 12:13:37.643 [46.197.24.97:27736 1 SMU] [Media] webp replacing: https://###################/wp-content/uploads/2022/###################.png 10/27/22 12:13:37.643 [46.197.24.97:27736 1 SMU] [Media] - replaced to: https://###################/wp-content/uploads/2022/06/###################.png.webp 10/27/22 12:13:37.658 [46.197.24.97:27736 1 SMU] [Core] Footer hook called 10/27/22 12:13:37.668 [46.197.24.97:27736 1 SMU] [Core] Footer check passed 10/27/22 12:13:37.668 [46.197.24.97:27736 1 SMU] [Ctrl] X Cache_control off - Admin configured URI Do not cache: /###################-fark-yaratmak/ 10/27/22 12:13:37.668 [46.197.24.97:27736 1 SMU] [Ctrl] X Cache_control -> no Cache => LiteSpeed Control::set_nocache()@362 => LiteSpeed Control->finalize()@662 => LiteSpeed LSC->send_headers()@494 => WP_Hook->apply_filters(ARRAY)@307 => WP_Hook->do_action(ARRAY)@331 => home/###################/public_html/wp-includes/load.php@476 10/27/22 12:13:37.668 [46.197.24.97:27736 1 SMU] [Vary] no custimzed vary 10/27/22 12:13:37.669 [46.197.24.97:27736 1 SMU] X-LiteSpeed-Cache-Control: no-cache 10/27/22 12:13:37.669 [46.197.24.97:27736 1 SMU] [Core] Footer check passed 10/27/22 12:13:37.669 [46.197.24.97:27736 1 SMU] bypass: Not cacheable 10/27/22 12:13:37.669 [46.197.24.97:27736 1 SMU] GUI bypassed by no counter 10/27/22 12:13:37.670 [46.197.24.97:27736 1 SMU] [Optm] start 10/27/22 12:13:37.670 [46.197.24.97:27736 1 SMU] [Data] load url file: lp_course 10/27/22 12:13:37.673 [46.197.24.97:27736 1 SMU] [CSS] Added queue_ccss [url_tag] lp_course [UA] Mozilla/5.0 (Windows NT 10.0 Win64 x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36 [vary] +webp [uid] 0 10/27/22 12:13:37.673 [46.197.24.97:27736 1 SMU] [Tag] Add --- CCSS.cadab3e9ae2203af396e23174f25643f 10/27/22 12:13:37.673 [46.197.24.97:27736 1 SMU] [Optm] CCSS set to OFF due to CCSS not generated yet 10/27/22 12:13:37.679 [46.197.24.97:27736 1 SMU] [Data] load url file: https://###################/###################-fark-yaratmak 10/27/22 12:13:37.680 [46.197.24.97:27736 1 SMU] [UCSS] Added queue_ucss [url_tag] https://###################/###################-fark-yaratmak [UA] Mozilla/5.0 (Windows NT 10.0 Win64 x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36 [vary] +webp [uid] 0 10/27/22 12:13:37.680 [46.197.24.97:27736 1 SMU] [Tag] Add --- UCSS.ed3297584e716ec0cce005f7f9af8dc7 10/27/22 12:13:37.681 [46.197.24.97:27736 1 SMU] [CSS] Load local [css] home/###################/public_html/wp-includes/css/dist/block-library/style.min.css [27-Oct-2022 09:13:37 UTC] PHP Fatal error: Uncaught Error: Class LiteSpeed Lib CSS_MIN UriRewriter not found in home/###################/public_html/wp-content/plugins/litespeed-cache/src/optimizer.cls.php:247 Stack trace: #0 home/###################/public_html/wp-content/plugins/litespeed-cache/src/optimizer.cls.php(107): LiteSpeed Optimizer->load_file() #1 home/###################/public_html/wp-content/plugins/litespeed-cache/src/optimize.cls.php(776): LiteSpeed Optimizer->serve() #2 home/###################/public_html/wp-content/plugins/litespeed-cache/src/optimize.cls.php(305): LiteSpeed Optimize->_build_hash_url() #3 home/###################/public_html/wp-content/plugins/litespeed-cache/src/optimize.cls.php(238): LiteSpeed Optimize->_optimize() #4 home/###################/public_html/wp-includes/class-wp-hook.php(307): LiteSpeed Optimize->finalize() #5 home/###################/public_html/wp-includes/plugin.php(191): WP_Hook->apply_filters() #6 /home/admin/domains/ in home/###################/public_html/wp-content/plugins/litespeed-cache/src/optimizer.cls.php on line 247Expand I also get different errors when I activate the cache and VPI features on these pages. For example: PHP Fatal error: Uncaught Error: Class LiteSpeed VPI not found in /home/###################/public_html/wp-content/plugins/litespeed-cache/src/root.cls.php:206 Stack trace: #0 /###################/public_html/wp-content/plugins/litespeed-cache/src/metabox.cls.php(161): LiteSpeed Root::cls() #1 /home/###################/public_html/wp-includes/class-wp-hook.php(307): LiteSpeed Metabox->lazy_img_excludes() #2 /home/###################/public_html/wp-includes/plugin.php(191): WP_Hook->apply_filters() #3 /home/###################/public_html/wp-content/plugins/litespeed-cache/src/media.cls.php(543): apply_filters() #4 /home/###################/public_html/wp-content/plugins/litespeed-cache/src/media.cls.php(476): LiteSpeed Media->_parse_img() #5 /home/###################/public_html/wp-content/plugins/litespeed-cache/src/media.cls.php(434): LiteSpeed Media->_finalize() #6 /home/###################/public_html/wp-includes in /home/###################/public_html/wp-content/plugins/litespeed-cache/src/root.cls.php on line 206 [27-Oct-2022 09:56:20 UTC] PHP Notice: Undefined variable: active_product in /home/###################/public_html/wp-content/themes/eduma-child/inc/templates/course-card.php on line 50 [27-Oct-2022 09:56:20 UTC] PHP Notice: Undefined variable: active_product in /home/###################/public_html/wp-content/themes/eduma-child/inc/templates/course-card.php on line 50 [27-Oct-2022 09:56:20 UTC] PHP Notice: Undefined variable: active_product in /home/###################/public_html/wp-content/themes/eduma-child/inc/templates/course-card.php on line 50 Note: I put ################### to hide some fields for security reasons. This topic was modified 1 month ago by Omer Faruk. What happens if you de-install and install the cache plugin? Already tried? @CacheCrawler No, I havent tried. Why would it be associated with it? Because there is no logical explanation for your reported issue. Webp versions of hundreds of photos were created. Many optimization adjustments have been made on the server. Will uninstalling and reinstalling the plugin completely destroy them? No, created images are not affected from deinstallation. You can backup (export) all settings and restore (import) them after new installation. Go to Toolbox -> Import/Export Tab. if plugin files are not corrupted , I can only think of plugin conflict somehow suggest to create a stage site and disable all other plugins and only enable LSCWP, see if these error still shows up @CacheCrawler Of course I can do that, but already courses and events are pages created with a different plugin. Im using Learnpress and WP Events Manager for this. If I disable these plugins, I will not be able to test the courses and events pages. Hi, yes, thats why I suggested to create a stage site and test on that , so it wont impact your live site. Best regards,
LiteCache Rush: Speed comes from using less, not from doing it faster
Reference